U.S. patent application number 14/411847 was filed with the patent office on 2015-06-11 for method and apparatus for periodically changing frequency in wireless power transfer.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is Jaesung Lee, Jeongkyo Seo. Invention is credited to Jaesung Lee, Jeongkyo Seo.
Application Number | 20150162785 14/411847 |
Document ID | / |
Family ID | 49882163 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150162785 |
Kind Code |
A1 |
Lee; Jaesung ; et
al. |
June 11, 2015 |
METHOD AND APPARATUS FOR PERIODICALLY CHANGING FREQUENCY IN
WIRELESS POWER TRANSFER
Abstract
Disclosed are a wireless power transfer apparatus, and a method
of changing a frequency in the wireless power transfer apparatus,
in which the magnetic field intensity in a specific frequency band
is decreased by periodically changing the frequency of a wireless
power signal, so that it is possible to spread a frequency
spectrum. To this end, a wireless power transfer apparatus includes
a power transmission unit and a control unit. The power
transmission unit generates a wireless power signal for
transferring wireless power based on a carrier signal. The control
unit determines a sweep frequency range and sweep period for the
carrier signal and controls the power transmission unit to
periodically change the frequency of the wireless power signal by
periodically changing the frequency of the carrier signal based on
the determined sweep frequency range and sweep period.
Inventors: |
Lee; Jaesung; (Suwon-Si,
KR) ; Seo; Jeongkyo; (Anyang-Si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lee; Jaesung
Seo; Jeongkyo |
Suwon-Si
Anyang-Si |
|
KR
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
49882163 |
Appl. No.: |
14/411847 |
Filed: |
July 6, 2012 |
PCT Filed: |
July 6, 2012 |
PCT NO: |
PCT/KR2012/005392 |
371 Date: |
December 29, 2014 |
Current U.S.
Class: |
307/104 |
Current CPC
Class: |
H02J 50/12 20160201;
H02J 5/005 20130101; H02J 50/90 20160201; H02J 7/0029 20130101;
H02J 7/025 20130101; H02J 50/40 20160201; H04B 5/0037 20130101;
H02J 50/80 20160201; G06F 1/26 20130101 |
International
Class: |
H02J 17/00 20060101
H02J017/00; H04B 5/00 20060101 H04B005/00 |
Claims
1. A wireless power transfer apparatus, comprising: a power
transmission unit configured to generate a wireless power signal
for transferring wireless power based on a carrier signal; and a
control unit configured to determine a sweep frequency range and
sweep period for the carrier signal and control the power
transmission unit to periodically change the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the determined sweep frequency range and
sweep period.
2. The wireless power transfer apparatus of claim 1, wherein the
sweep frequency range is a frequency range including a
predetermined frequency.
3. The wireless power transfer apparatus of claim 2, wherein the
predetermined frequency is a frequency representing a resonance
frequency or maximum wireless power transfer efficiency in wireless
power transfer.
4. The wireless power transfer apparatus of claim 1, wherein the
sweep frequency range is a frequency range between first and second
maximum frequencies, and the first maximum frequency is a frequency
representing the maximum wireless power transfer efficiency within
a first frequency range and the second maximum frequency is a
frequency representing the maximum wireless power transfer
efficiency within a second frequency range.
5. The wireless power transfer apparatus of claim 1, wherein the
power transmission unit obtains power transfer information from a
wireless power receiving apparatus receiving the wireless power
signal, and the control unit generates a transfer profile based on
the obtained power transfer information and determines the sweep
frequency range based on the transfer profile.
6. The wireless power transfer apparatus of claim 5, wherein the
power transmission unit sequentially transfers wireless power
signals having different frequencies and obtains power transfer
information corresponding to each of the sequentially transferred
wireless power signals.
7. The wireless power transfer apparatus of claim 5, wherein the
power transfer information includes information related to at least
one of a receiving-side voltage of the wireless power receiving
apparatus, a receiving-side current of the wireless power receiving
apparatus, a first reference voltage and a second reference
voltage.
8. The wireless power transfer apparatus of claim 7, wherein the
sweep frequency range is a frequency range corresponding to the
range in which the receiving-side voltage is the first reference
voltage or less and the second reference voltage or more.
9. The wireless power transfer apparatus of claim 7, wherein the
first reference voltage is determined based on whether or not the
first reference voltage is a voltage at which damage on the
wireless power receiving apparatus is to be caused, and the second
reference voltage is determined based on whether or not the second
reference voltage is a voltage at which the wireless power
receiving apparatus is to receive wireless power from the wireless
power transfer apparatus.
10. The wireless power transfer apparatus of claim 7, wherein the
transfer profile represents a relationship between the frequency of
the wireless power signal and at least one of the receiving-side
voltage, a transfer efficiency and a transfer gain.
11. The wireless power transfer apparatus of claim 10, wherein the
transfer efficiency is a ratio between transfer power of the
wireless power transfer apparatus and receiving power of the
wireless power receiving apparatus, and the transfer gain is a
ratio between a transmitting-side voltage of the wireless power
transfer apparatus and a receiving-side voltage of the wireless
power receiving apparatus.
12. The wireless power transfer apparatus of claim 10, wherein the
control unit extracts, as a reference frequency, a frequency of
which primary differential value is 0' and secondary differential
value is a negative number with respect to at least one the
receiving-side voltage, the transfer efficiency and the transfer
gain, and determines the sweep frequency range based on the
reference frequency.
13. The wireless power transfer apparatus of claim 12, wherein the
control unit determines a specific frequency range including the
reference frequency as the sweep frequency range.
14. The wireless power transfer apparatus of claim 12, wherein the
reference frequency includes first and second frequencies, and the
sweep frequency range is a frequency range between the first and
second frequencies.
15. The wireless power transfer apparatus of claim 12, wherein the
reference frequency includes N frequencies, and the control unit
selects two frequencies from the N frequencies and determines a
frequency range between the two selected frequencies as the sweep
frequency range.
16. The wireless power transfer apparatus of claim 15, wherein the
two selected frequencies are two frequencies closest to the
resonance frequency among the N frequencies in the wireless power
transfer.
17. The wireless power transfer apparatus of claim 12, wherein the
reference frequency includes N frequencies, and the control unit
selects a specific frequency from the N frequencies and determines
a specific frequency range including the specific frequency as the
sweep frequency range.
18. The wireless power transfer apparatus of claim 17, wherein the
specific frequency is a frequency at which at least one of the
receiving-side voltage the transfer efficiency and the transfer
gain is maximized or a frequency closest to the resonance frequency
among the N frequencies in the wireless power transfer.
19. The wireless power transfer apparatus of claim 13, wherein the
specific frequency range is determined based on whether or not the
wireless power receiving apparatus is to receive wireless power
from the wireless power transfer apparatus based on at least one of
the receiving-side voltage the transfer efficiency and the transfer
gain on the transfer profile.
20. The wireless power transfer apparatus of claim 5, wherein the
wireless power receiving apparatus includes a plurality of wireless
power receiving apparatuses, and the control unit generates a
plurality of transfer profiles respectively corresponding to the
plurality of wireless power receiving apparatuses and determines
the sweep frequency range based on the plurality of transfer
profiles.
21. The wireless power transfer apparatus of claim 20, wherein the
control unit selects at least on transfer profile from the
plurality of transfer profiles and determines the sweep frequency
range based on the selected at least one transfer profile.
22. The wireless power transfer apparatus of claim 21, wherein the
selecting of the at least one transfer profile from the plurality
of transfer profiles is performed based on at least one of whether
or not the first reference voltage is a voltage at which damage on
the wireless power receiving apparatus is to be caused and whether
or not the second reference voltage is a voltage at which the
wireless power receiving apparatus is to receive wireless power
from the wireless power transfer apparatus.
23. The wireless power transfer apparatus of claim 20, wherein the
control unit generates a reference transfer profile based on the
plurality of transfer profiles and determines the sweep frequency
range based on the generated reference transfer profile.
24. The wireless power transfer apparatus of claim 23, wherein the
reference transfer profile is generated by processing the plurality
of transfer profiles using a statistical method.
25. The wireless power transfer apparatus of claim 24, wherein the
statistical method is a method based on at least one the average,
dispersion and standard deviation of the plurality of transfer
profiles.
26. The wireless power transfer apparatus of claim 1, wherein the
sweep period includes a plurality of sub-sweep period, and the
control unit selects a specific sub-sweep period from the plurality
of sub-sweep periods based on data to be transferred to the
wireless power receiving apparatus and controls the power
transmission unit to change the frequency of the wireless power
signal by periodically changing the frequency of the carrier signal
based on the selected specific sub-sweep period.
27. The wireless power transfer apparatus of claim 26, wherein the
wireless power receiving apparatus detects a specific sweep period
from the wireless power signal and recovers the transferred data
based on the detected specific sweep period.
28. The wireless power transfer apparatus of claim 26, wherein the
plurality of sub-sweep periods are first and second sub-sweep
periods, and the first sub-sweep period is a period corresponding
to data `0` and the second sub-sweep period is a period
corresponding to data `1.`
29. A method of changing a frequency in a wireless power transfer
apparatus, the method comprising: generating a wireless power
signal for transferring wireless power based on a carrier signal;
determining a sweep frequency range and sweep period for the
carrier signal; and periodically changing the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the determined sweep frequency range and
sweep period.
30. The method of claim 29, wherein the determining of the sweep
frequency range comprises: obtaining power transfer information
from a wireless power receiving apparatus receiving the wireless
power signal; generating a transfer profile based on the obtained
power transfer information; and determining the sweep frequency
range based on the transfer profile.
31. The method of claim 30, wherein the transfer profile represents
a relationship between the frequency of the wireless power signal
and at least one of a receiving-side voltage, a transfer efficiency
and a transfer gain.
32. The method of claim 31, wherein the determining of the sweep
frequency range comprises: extracting, as a reference frequency, a
frequency of which primary differential value is 0' and secondary
differential value is a negative number with respect to at least
one the receiving-side voltage, the transfer efficiency and the
transfer gain; and determining the sweep frequency range based on
the reference frequency.
Description
TECHNICAL FIELD
[0001] The present invention relates to wireless power transfer,
and more particularly, to a method and apparatus for periodically
changing a frequency based on power transfer information in
wireless power transfer.
BACKGROUND ART
[0002] While a method of supplying power by wire to wireless power
receiving apparatuses was traditionally used, a method of supplying
power by wireless to wireless power receiving apparatuses without
contact has been used in recent years. A wireless power receiving
apparatus for receiving power by wireless may be directly driven by
the received wireless power, or may charge a battery using the
received wireless power and be driven by the charged power.
[0003] The Wireless Power Consortium dealing with technologies for
wireless power transfer using magnetic induction published a
standard document for interoperability in wireless power transfer
on Apr. 12, 2010, entitled "System Description Wireless Power
Transfer" (Volume 1, Lower Power, Part 1: Interface Definition,
Version 1.00 Release Candidate 1). The standard document published
by the Wireless Power Consortium discloses a method of transmitting
power from one wireless power transfer apparatus to another
wireless power transfer apparatus using magnetic induction.
DISCLOSURE OF INVENTION
Solution to Problem
Disclosure of the Invention
[0004] Therefore, an object of the present invention is to provide
a wireless power transfer apparatus (or Wireless power
transmitter), and a method of changing a frequency in the wireless
power transfer apparatus.
[0005] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described herein, there is provided a wireless power transfer
apparatus, including: a power transmission unit configured to
generate a wireless power signal for transferring wireless power
based on a carrier signal; and a control unit configured to
determine a sweep frequency range and sweep period for the carrier
signal and control the power transmission unit to periodically
change the frequency of the wireless power signal by periodically
changing the frequency of the carrier signal based on the
determined sweep frequency range and sweep period.
[0006] The sweep frequency range may be a frequency range including
a predetermined frequency.
[0007] The predetermined frequency may be a frequency representing
a resonance frequency or maximum wireless power transfer efficiency
in wireless power transfer.
[0008] The sweep frequency range may be a frequency range between
first and second maximum frequencies, and the first maximum
frequency may be a frequency representing the maximum wireless
power transfer efficiency within a first frequency range and the
second maximum frequency may be a frequency representing the
maximum wireless power transfer efficiency within a second
frequency range.
[0009] The power transmission unit may obtain power transfer
information from a wireless power receiving apparatus receiving the
wireless power signal, and the control unit may generate a transfer
profile based on the obtained power transfer information and
determine the sweep frequency range based on the transfer
profile.
[0010] The power transmission unit may sequentially transfer
wireless power signals having different frequencies and obtain
power transfer information corresponding to each of the
sequentially transferred wireless power signals.
[0011] The power transfer information may include information
related to at least one of a receiving-side voltage of the wireless
power receiving apparatus, a receiving-side current of the wireless
power receiving apparatus, a first reference voltage and a second
reference voltage.
[0012] The sweep frequency range may be a frequency range
corresponding to the range in which the receiving-side voltage is
the first reference voltage or less and the second reference
voltage or more.
[0013] The first reference voltage may be determined based on
whether or not the first reference voltage is a voltage at which
damage on the wireless power receiving apparatus is to be caused,
and the second reference voltage may be determined based on whether
or not the second reference voltage is a voltage at which the
wireless power receiving apparatus is to receive (or could receive)
wireless power from the wireless power transfer apparatus.
[0014] The transfer profile may represent a relationship between
the frequency of the wireless power signal and at least one of the
receiving-side voltage, a transfer efficiency and a transfer
gain.
[0015] The transfer efficiency may be a ratio between transfer
power of the wireless power transfer apparatus and receiving power
of the wireless power receiving apparatus, and the transfer gain
may be a ratio between a transmitting-side voltage of the wireless
power transfer apparatus and a receiving-side voltage of the
wireless power receiving apparatus.
[0016] The control unit may extract, as a reference frequency, a
frequency of which primary differential value is 0' and secondary
differential value is a negative number with respect to at least
one the receiving-side voltage, the transfer efficiency and the
transfer gain, and determine the sweep frequency range based on the
reference frequency.
[0017] The control unit may determine a specific frequency range
including the reference frequency as the sweep frequency range.
[0018] The reference frequency may include first and second
frequencies, and the sweep frequency range may be a frequency range
between the first and second frequencies.
[0019] The reference frequency may include N frequencies, and the
control unit may select two frequencies from the N frequencies and
determine a frequency range between the two selected frequencies as
the sweep frequency range.
[0020] The two selected frequencies may be two frequencies closest
to the resonance frequency among the N frequencies in the wireless
power transfer.
[0021] The reference frequency may include N frequencies, and the
control unit may select a specific frequency from the N frequencies
and determine a specific frequency range including the specific
frequency as the sweep frequency range.
[0022] The specific frequency may be a frequency at which at least
one of the receiving-side voltage the transfer efficiency and the
transfer gain is maximized or a frequency closest to the resonance
frequency among the N frequencies in the wireless power
transfer.
[0023] The specific frequency range may be determined based on
whether or not the wireless power receiving apparatus is to receive
wireless power from the wireless power transfer apparatus based on
at least one of the receiving-side voltage the transfer efficiency
and the transfer gain on the transfer profile.
[0024] The wireless power transfer receiving apparatus may include
a plurality of wireless power receiving apparatuses, and the
control unit may generate a plurality of transfer profiles
respectively corresponding to the plurality of wireless power
receiving apparatuses and determine the sweep frequency range based
on the plurality of transfer profiles.
[0025] The control unit may select at least on transfer profile
from the plurality of transfer profiles and determine the sweep
frequency range based on the selected at least one transfer
profile.
[0026] The selecting of the at least one transfer profile from the
plurality of transfer profiles may be performed based on at leas
one of whether or not the first reference voltage is a voltage at
which damage on the wireless power receiving apparatus is to be
caused and whether or not the second reference voltage is a voltage
at which the wireless power receiving apparatus is to receive (or
could receive) wireless power from the wireless power transfer
apparatus.
[0027] The control unit may generate a reference transfer profile
based on the plurality of transfer profiles and determine the sweep
frequency range based on the generated reference transfer
profile.
[0028] The reference transfer profile may be generated by
processing the plurality of transfer profiles using a statistical
method.
[0029] The statistical method may be a method based on at least one
the average, dispersion and standard deviation of the plurality of
transfer profiles.
[0030] The sweep period may include a plurality of sub-sweep
period, and the control unit may select a specific sub-sweep period
from the plurality of sub-sweep periods based on data to be
transferred to the wireless power receiving apparatus and control
the power transmission unit to change the frequency of the wireless
power signal by periodically changing the frequency of the carrier
signal based on the selected specific sub-sweep period.
[0031] The wireless power receiving apparatus may detect a specific
sweep period from the wireless power signal and recover the
transferred data based on the detected specific sweep period.
[0032] The plurality of sub-sweep periods may be first and second
sub-sweep periods, and the first sub-sweep period may be a period
corresponding to data `0` and the second sub-sweep period is a
period corresponding to data `1.`.
[0033] To achieve the above aspect of the present invention, there
is provided a method of changing the frequency of a wireless power
signal transferred by a wireless power transfer apparatus, the
method including: generating a wireless power signal for
transferring wireless power based on a carrier signal; determining
a sweep frequency range and sweep period for the carrier signal;
and periodically changing the frequency of the wireless power
signal by periodically changing the frequency of the carrier signal
based on the determined sweep frequency range and sweep period.
[0034] The determining of the sweep frequency range may include
obtaining power transfer information from a wireless power
receiving apparatus receiving the wireless power signal; generating
a transfer profile based on the obtained power transfer
information; and determining the sweep frequency range based on the
transfer profile.
[0035] The transfer profile may represent a relationship between
the frequency of the wireless power signal and at least one of a
receiving-side voltage, a transfer efficiency and a transfer
gain.
[0036] The determining of the sweep frequency range may include
extracting, as a reference frequency, a frequency of which primary
differential value is 0' and secondary differential value is a
negative number with respect to at least one the receiving-side
voltage, the transfer efficiency and the transfer gain; and
determining the sweep frequency range based on the reference
frequency.
[0037] According to an embodiment, there is provided a wireless
power transfer apparatus, and a method of changing a frequency in
the wireless power transfer apparatus, in which the magnetic field
intensity in a specific frequency band is decreased by periodically
changing the frequency of a wireless power signal, so that it is
possible to spread a frequency spectrum.
[0038] According to the wireless power transfer apparatus and the
method of changing a frequency in the wireless power transfer
apparatus, the frequency spectrum of a wireless power signal can be
spread by sweeping the frequency of the wireless power signal.
Accordingly, the magnetic field intensity in the specific frequency
band is decreased, so that it is possible to cope with
electromagnetic compatibility (EMC) regulations.
MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS
[0039] The technology disclosed in this specification is applied to
wireless power transfer. However, the technology disclosed in this
specification is not limited thereto, and may be applied to all
power transfer systems and methods, wireless charging circuits and
methods, and methods and apparatuses using power transferred by
wireless, to which the scope and spirit of the technology can be
applied.
[0040] Technical terms used in this specification are used to
merely illustrate specific embodiments, and should be understood
that they are not intended to limit the present disclosure. As far
as not being defined differently, all terms used herein including
technical or scientific terms may have the same meaning as those
generally understood by an ordinary person skilled in the art to
which the present disclosure belongs to, and should not be
construed in an excessively comprehensive meaning or an excessively
restricted meaning. In addition, if a technical term used in the
description of the present disclosure is an erroneous term that
fails to clearly express the idea of the present disclosure, it
should be replaced by a technical term that can be properly
understood by the skilled person in the art. In addition, general
terms used in the description of the present disclosure should be
construed according to definitions in dictionaries or according to
its front or rear context, and should not be construed to have an
excessively restrained meaning.
[0041] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. It will be further understood that the terms
"includes" and/or "including," when used in this specification,
specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence and/or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0042] In the following description, suffixes "module" and "unit or
portion" for components used herein in description are merely
provided only for facilitation of preparing this specification, and
thus they are not granted a specific meaning or function.
[0043] It will be understood that, although the terms "first,"
"second," etc. may be used herein to describe various elements,
these elements should not be limited by these terms. These terms
are only used to distinguish one element from another element.
Thus, a "first" element discussed below could also be termed as a
"second" element without departing from the teachings of the
present invention.
[0044] In the drawings, the thickness of layers, films and regions
are exaggerated for clarity. Like numerals refer to like elements
throughout.
[0045] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. It will also be apparent
to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the spirit or scope of the invention. Thus, it is intended
that the present invention cover modifications and variations of
this invention provided they come within the scope of the appended
claims and their equivalents.
[0046] Description will now be given in detail of a wireless power
transfer apparatus and a method of changing a frequency in the
wireless power transfer apparatus a according to an embodiment,
with reference to the accompanying drawings.
[0047] FIG. 1 is an exemplary view conceptually illustrating a
wireless power transfer apparatus and an electronic device
according to embodiments of the present disclosure.
[0048] As can be seen with reference to FIG. 1, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may be a
power transmission apparatus that transmits required power by
wireless to the electronic device (or Wireless power receiver)
200.
[0049] Therefore, the electronic device (or Wireless power
receiver) 200 may be referred to as a wireless power receiving
apparatus.
[0050] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may be a wireless charging apparatus that charges
a battery of the electronic device (or wireless power receiving
apparatus, Wireless power receiver) 200 by transferring power by
wireless to the electronic device (or Wireless power receiver) 200.
An embodiment implemented using the wireless power transfer
apparatus (or Wireless power transmitter) 100 will be described
later with reference to FIG. 9.
[0051] In addition, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may be implemented as various types
of apparatuses for transmitting power to the electronic device (or
Wireless power receiver) 200 that requires the power in the state
in which the wireless power transfer apparatus (or Wireless power
transmitter) 100 does not come in contact with the electronic
device (or Wireless power receiver) 200.
[0052] Meanwhile, it should be construed that the electronic device
receiving power by wireless includes all electronic devices, e.g.,
a mobile phone, a cellular phone, a smart phone, a personal digital
assistant (PDA), a portable multimedia player (PMP) and a tablet or
multimedia devices, as well as input/output apparatuses such as a
keyboard, a mouse and a video or audio auxiliary output device.
[0053] The electronic device (or Wireless power receiver) 200, as
will be described later, may be a mobile communication terminal
(e.g., a mobile phone, cellular phone or table phone) or a
multimedia apparatus. An embodiment in which the electrode
apparatus is implemented as a mobile terminal will be described
later with reference to FIG. 10.
[0054] Meanwhile, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may use one or more wireless power
transmission methods so as to transmit power by wireless to the
electronic device (or Wireless power receiver) 200 without any
contact between the wireless power transfer apparatus (or Wireless
power transmitter) 100 and the electronic device (or Wireless power
receiver) 200. That is, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may transmit power using one or
more of inductive coupling and electromagnetic resonance coupling.
Here, the inductive coupling is based on an electromagnetic
induction phenomenon occurring due to the wireless power signal,
and the electromagnetic resonance coupling is based on an
electromagnetic resonance phenomenon occurring due to a wireless
power signal of a specific frequency.
[0055] The wireless power transfer according to the inductive
coupling is a technique for transferring power by wireless using
primary and secondary coils. In the wireless power transfer
according to the inductive coupling, current is induced to another
coil by a variable magnetic field generated in one coil by the
electromagnetic induction phenomenon, thereby transferring
power.
[0056] In the wireless power transfer according the electromagnetic
resonance coupling, electromagnetic resonance is generated in the
electronic device (or Wireless power receiver) 200 by the wireless
power signal transferred from the wireless power transfer apparatus
(or Wireless power transmitter) 100, and power is transmitted from
the wireless power transfer apparatus (or Wireless power
transmitter) 100 to the electronic device (or Wireless power
receiver) 200 by the electromagnetic resonance phenomenon.
[0057] Hereinafter, embodiments of the wireless power transfer
apparatus (or Wireless power transmitter) 100 and the electronic
devices 200, which are disclosed in the present disclosure, will be
described in detail. In adding reference numerals to components of
each drawing, it is noted that the same reference numerals are used
to designate the same components even though the same components
are shown in other drawings.
[0058] FIGS. 2A and 2B are block diagrams illustrating
configurations of the wireless power transfer apparatus (or
Wireless power transmitter) 100 and the electronic device (or
Wireless power receiver) 200, applicable in embodiments of the
present disclosure, respectively.
[0059] Referring to FIG. 2A, the wireless power transfer apparatus
(or Wireless power transmitter) 100 includes a power transmission
unit 110. The power transmission unit 110 may include a power
conversion unit 111 and a power transmission control unit 112.
[0060] The power conversion unit 111 converts power supplied from a
power supply unit 190 of the wireless power transfer apparatus (or
Wireless power transmitter) 100 into a wireless power signal and
transmits the converted wireless power signal to the electronic
device (or Wireless power receiver) 200. The wireless power signal
transmitted by the power conversion unit 111 is formed in a
magnetic field or electromagnetic field which is oscillated. To
this end, the power conversion unit 111 may include a coil through
which the wireless power signal is generated.
[0061] The power conversion unit 111 may include a component for
generating a wireless power signal according to each of the
wireless power transmission methods.
[0062] In some embodiments, the power conversion unit 111 may
include a primary coil for generating a variable magnetic field so
as to induce current to a secondary coil of the electronic device
(or Wireless power receiver) 200 according to the inductive
coupling. In some embodiment, the power conversion unit 111 may
include a coil (or antenna) for generating a magnetic field having
a specific frequency so as to cause a resonance phenomenon to occur
in the electronic device (or Wireless power receiver) 200 according
to the electromagnetic resonance coupling.
[0063] In some embodiment, the power conversion unit 111 may
transmit power using one or more of the inductive coupling and the
electromagnetic resonance coupling.
[0064] Components according to the inductive coupling among the
components included in the power conversion unit 111 will be
described later with reference to FIGS. 4 and 5, and components
according to the electromagnetic resonance coupling among the
components included in the power conversion unit 111 will be
described later with reference to FIGS. 7 and 8.
[0065] Meanwhile, the power conversion unit 111 may further include
a circuit capable of controlling characteristics of frequency used
to generate the wireless power signal, applied voltage, current,
etc.
[0066] The power transmission control unit 112 controls each of the
components included in the power transmission unit 110. In some
embodiments, the power transmission control unit 112 may be
implemented to be integrated with another control unit (not shown)
controlling the wireless power transfer apparatus (or Wireless
power transmitter) 100.
[0067] Meanwhile, the area in which the wireless power signal can
approach may be divided into two areas. First, an active area
refers to an area through which the wireless power signal for
transmitting power to the electronic device (or Wireless power
receiver) 200 passes. Next, a semi-active area refers to an
interest area in which the wireless power transfer apparatus (or
Wireless power transmitter) 100 can detect the existence of the
electronic device (or Wireless power receiver) 200. Here, the power
transmission control unit 112 may detect whether the electronic
device (or Wireless power receiver) 200 has been placed in or
removed from the active area or the semi-active area. Specifically,
the power transmission control unit 112 may detect whether the
electronic device (or Wireless power receiver) 200 has been
displaced in the active area or the semi-active area, using the
wireless power signal generated in the power conversion unit 111 or
using a separate sensor. For example, the power transmission
control unit 112 may detect the existence of the electronic device
(or Wireless power receiver) 200 by monitoring whether or not the
property of power for generating the wireless power signal in the
power conversion unit 111 is changed due to the wireless power
signal influenced by the electronic device (or Wireless power
receiver) 200 existing in the semi-active area. However, the active
area and the semi-active area may be changed depending on the
wireless power transmission method including the inductive
coupling, the electromagnetic resonance coupling, etc.
[0068] The power transmission control unit 112 may determine
whether to perform a process of identifying the electronic device
(or Wireless power receiver) 200 or to start wireless power
transfer, based on the result obtained by detecting the existence
of the electronic device (or Wireless power receiver) 200.
[0069] The power transmission control unit 112 may determine one or
more characteristics of the frequency, voltage and current of the
power conversion unit 111 for generating the wireless power signal.
The determination of the characteristics may be made under a
condition of the wireless power transfer apparatus (or Wireless
power transmitter) 100 or under a condition of the electronic
device (or Wireless power receiver) 200. In some embodiments, the
power transmission control unit 112 may determine the
characteristics based on device identification information of the
electronic device (or Wireless power receiver) 200. In some
embodiments, the power transmission control unit 112 may determined
the characteristics based on required power information of the
electronic device (or Wireless power receiver) 200 or profile
information on the required power of the electronic device (or
Wireless power receiver) 200. The power transmission control unit
112 may receive a power control message from the electronic device
(or Wireless power receiver) 200. The power transmission control
unit 112 may determine one or more characteristics of the
frequency, voltage and current of the power conversion unit 111,
based on the received power control message. In addition, the power
transmission control unit 112 may perform another control operation
based on the power control message.
[0070] For example, the power transmission control unit 112 may
determine one or more characteristics of the frequency, voltage and
current used to generate the wireless power signal, based on the
power control message containing one or more of rectified electric
energy information, charging state information and identification
information of the electronic device (or Wireless power receiver)
200.
[0071] The power transmission control unit 112 may control the
power conversion unit 111 to perform scanning on frequencies in a
certain range so as to obtain power transfer information for each
frequency of the wireless power receiving apparatus displaced in
the active area or the semi-active area.
[0072] The scanning may mean an operation or method of identifying
transition of the power transfer information according to the
change in frequency of the wireless power signal. For example, the
scanning may mean an operation in which wireless power signals
having different frequencies are sequentially transferred by the
wireless power transfer apparatus (or Wireless power transmitter)
100, and the wireless power transfer apparatus (or Wireless power
transmitter) 100 obtain power transfer information corresponding to
each of the sequentially transferred wireless power signals.
[0073] The power transfer information may include information
related to at least one of a voltage of the wireless power
receiving apparatus, a current of the wireless power receiving
apparatus, a first reference voltage and a second reference
voltage.
[0074] Here, the first reference voltage is determined based on
whether or not the first reference voltage is a voltage that may
cause damage on the wireless power receiving apparatus, and the
second reference voltage is determined based on whether or not the
second reference voltage is a voltage at which the wireless power
receiving apparatus can receive wireless power from the wireless
power transfer apparatus.
[0075] As another control operation using the power control
message, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may perform a general control operation related to
wireless power transfer based on the power control message. For
example, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may receive information to be audibly or visibly
output in relation to the electronic device (or Wireless power
receiver) 200 or may receive information necessary for
authentication between devices, through the power control
message.
[0076] In some embodiments, the power transmission control unit 112
may receive the power control message through the wireless power
signal. In some embodiments, the power transmission control unit
112 may receive the power control message using a method of
receiving user data.
[0077] To receive power control message, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may further
include a modulation/demodulation unit 113 electrically connected
to the power conversion unit 111. The modulation/demodulation unit
113 may be used to receive the power control message by
demodulating the wireless power signal modulated by the electronic
device (or Wireless power receiver) 200. The method in which the
power conversion unit 111 receives a power control message using a
wireless power signal will be described later with reference to
FIGS. 11 to 13.
[0078] In addition, the power transmission control unit 112 may
obtain the power control message by receiving user data containing
the power control message using a communication means (not shown)
included in the wireless power transfer apparatus (or Wireless
power transmitter) 100.
[0079] FIG. 2B illustrates a configuration of the electronic device
(or Wireless power receiver) 200.
[0080] Referring to FIG. 2B, the electronic device (or Wireless
power receiver) 200 includes a power supply unit 290. The power
supply unit 290 supplies power necessary for the operation of the
electronic device (or Wireless power receiver) 200. The power
supply unit 290 may include a power receiving unit 291 and a power
receiving control unit 292.
[0081] The power receiving unit 291 receives power transmitted by
wireless from the wireless power transfer apparatus (or Wireless
power transmitter) 100.
[0082] The power receiving unit 291 may include a component
necessary for receiving the wireless power signal according to the
wireless power transmission method. The power receiving unit 291
may receive power according to one or more wireless power
transmission methods. In this case, the power receiving unit 291
may include components required according to each of the wireless
power transmission methods.
[0083] First, the power receiving unit 291 may include a coil for
receiving a wireless power signal transmitted in the form of a
magnetic or electromagnetic field having a vibration property.
[0084] For example, in some embodiments, the power receiving unit
291 may include a secondary coil to which current is induced by a
magnetic field changed as a component according to the inductive
coupling. In some embodiments, the power receiving unit 291 may
include a resonance generation circuit and a coil in which
electromagnetic resonance is generated by a magnetic field having a
specific resonance frequency as a component according to the
electromagnetic resonance coupling.
[0085] However, in some embodiments, the power receiving unit 291
may receive power according to one or more of wireless power
transmission methods. In this case, the power receiving unit 291
may be implemented to receive power using one coil or may be
implemented to receive power using a coil formed according to each
of the wireless power transmission methods.
[0086] Embodiments according to the inductive coupling in the
components included in the power receiving unit 291 will be
described later with reference to FIGS. 4A and 4B. Embodiments
according to the electromagnetic resonance coupling in the
components included in the power receiving unit 291 will be
described later with reference to FIGS. 7A and 7B.
[0087] Meanwhile, the power receiving unit 291 may further include
a rectifying circuit and a smoothing circuit, which convert the
wireless power signal into a DC signal. The power receiving unit
291 may further include a circuit for preventing overvoltage or
overcurrent from being generated by the received power signal.
[0088] The power receiving control unit 292 controls each of the
components included in the power supply unit 290.
[0089] Specifically, the power receiving control unit 292 may
transmit a power control message to the wireless power transfer
apparatus (or Wireless power transmitter) 100. The power control
message may be used to start or finish transmitting a wireless
power signal to the wireless power transfer apparatus (or Wireless
power transmitter) 100. The power control message may be used to
instruct the wireless power transfer apparatus (or Wireless power
transmitter) 100 to control characteristics of the wireless power
signal.
[0090] In some embodiments, the power receiving control unit 292
may transfer the power control message through the wireless power
signal. In some embodiments, the power receiving control unit 292
may transfer the power control message through user data.
[0091] To transfer a power control message, the electronic device
(or Wireless power receiver) 200 may further include a
modulation/demodulation unit electrically connected to the power
receiving unit 291. The modulation/demodulation unit 293, like that
of the wireless power transfer apparatus (or Wireless power
transmitter) 100 described above, may be used to transfer the power
control message through the wireless power signal. The
modulation/demodulation unit 293 may be used as a means for
controlling current and/or voltage flowing through the power
conversion unit 111 of the wireless power transfer apparatus (or
Wireless power transmitter) 100. Hereinafter, the method in which
each of the modulation/demodulation units 113 and 293 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 and the electronic device (or Wireless power receiver) 200 is
used to transmit/receive the power control message through the
wireless power signal will be described.
[0092] The wireless power signal generated by the power conversion
unit 111 is received by the power receiving unit 291. In this case,
the power receiving control unit 292 controls the
modulation/demodulation unit 293 of the electronic device (or
Wireless power receiver) 200 to modulate the wireless power signal.
For example, the power receiving control unit 292 may perform a
modulation process by changing the reactance of the
modulation/demodulation 293 connected to the power receiving unit
291 so that the electric energy received from the wireless power
signal is changed depending on the reactance. The change in the
electric energy received from the wireless power signal results in
a change in current and/or voltage of the power conversion unit
111. In this case, the modulation/demodulation unit 113 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 performs a demodulation process by detecting the change in the
current and/or voltage of the power conversion unit 111.
[0093] That is, the power receiving control unit 292 generates a
packet containing a power control message to be transmitted to the
wireless power transfer apparatus (or Wireless power transmitter)
100 and demodulates the wireless power signal so that the packet is
contained in the wireless power signal. The power transmission
control unit 112 decodes the packet based on the result obtained by
performing the demodulation process of the modulation/demodulation
unit 113, so as to obtain the power control message containing the
packet. The detailed method in which the wireless power transfer
apparatus (or Wireless power transmitter) 100 obtains the power
control message will be described later with reference to FIGS. 11
to 13.
[0094] In some embodiments, the power receiving control unit 292
may transfer a power control message to the wireless power transfer
apparatus (or Wireless power transmitter) 100 by transferring user
data containing the power control message using a communication
means (not shown) included in the electronic device (or Wireless
power receiver) 200.
[0095] In addition, the power supply unit 290 may further include a
charging unit 298 and a battery 299.
[0096] The electronic device (or Wireless power receiver) 200
receiving power for its operation from the power supply unit 290
may be operated by the power transmitted from the wireless power
transfer apparatus (or Wireless power transmitter) 100, or may be
operated by the power charged to the battery 299 using the
transmitted power. In this case, the power receiving control unit
292 may control the charging unit 298 to perform the charging of
the battery using the transmitted power.
[0097] Hereinafter, the wireless power transfer apparatus and the
electronic device, applicable in the embodiments of the present
disclosure will be described.
[0098] First, the method in which the wireless power transfer
apparatus transmits power to the electronic device according to
embodiments supporting the inductive coupling will be described
with reference to FIGS. 3 to 5.
[0099] FIG. 3 illustrates a concept that power is transmitted by
wireless from the wireless power transfer apparatus to the
electronic device according to embodiments supporting the inductive
coupling.
[0100] The power transmission of the wireless power transfer
apparatus (or Wireless power transmitter) 100 according to the
inductive coupling will be described. If the intensity of current
flowing into a primary coil of the power transmission unit 110 is
changed, the magnetic field passing through the primary coil is
change by the current. The magnetic field changed as described
above generates an induced electromotive force at a secondary coil
in the electronic device (or Wireless power receiver) 200.
[0101] According to the inductive coupling, the power conversion
unit 111 of the wireless power transfer apparatus (or Wireless
power transmitter) 100 includes a transfer coil (Tx coil) 1111a
operating as a primary coil in magnetic induction. The power
receiving unit 291 of the electronic device (or Wireless power
receiver) 200 includes a receiving coil (Rx coil) 2911a operating
as a secondary coil in the magnetic induction.
[0102] First, the wireless power transfer apparatus (or Wireless
power transmitter) 100 and the electronic device (or Wireless power
receiver) 200 are displaced so that the transfer coil (Transmitting
coil or Tx coil) 1111a of the wireless power transfer apparatus (or
Wireless power transmitter) 100 and the receiving coil (or Rx coil)
2911a of the electronic device (or Wireless power receiver) 200
come close to each other. Then, if the power transmission control
unit 112 controls the current of the transfer coil (Transmitting
coil or Tx coil) 1111a to be changed, the power receiving unit 291
controls power to be supplied to the electronic device (or Wireless
power receiver) 200 using the electromotive force induced to the
receiving coil (or Rx coil) 2911a.
[0103] The efficiency of the wireless power transfer according to
the inductive coupling is little influenced by properties of
frequencies, but is influenced by the alignment and distance
between the wireless power transfer apparatus (or Wireless power
transmitter) 100 and the electronic device (or Wireless power
receiver) 200, which include the transfer coil (Transmitting coil
or Tx coil) 1111a and the receiving coil (or Rx coil) 2911a,
respectively.
[0104] Meanwhile, to perform the wireless power transfer according
to the inductive coupling, the wireless power transfer apparatus
(or Wireless power transmitter) 100 may include an interface
surface (not shown) in the form of a flat surface. One or more
electronic devices may be placed on the interface surface, and the
transfer coil (Transmitting coil or Tx coil) 1111a may be mounted
beneath the interface surface. In this case, a small vertical
spacing is formed between the transfer coil (Transmitting coil or
Tx coil) 1111a mounted beneath the interface surface and the
receiving coil (or Rx coil) 2911a of the electronic device (or
Wireless power receiver) 200 placed on the interface surface, and
thus the distance between the coils is sufficiently small so that
the wireless power transmission according to the inductive coupling
can be efficiently performed.
[0105] An alignment indicating unit (not shown) indicating a
position at which the electronic device (or Wireless power
receiver) 200 is to be placed may be formed on the interface
surface. The alignment indicating unit indicates a position of the
electronic device (or Wireless power receiver) 200, at which the
transfer coil (Transmitting coil or Tx coil) 1111a mounted beneath
the interface surface and the receiving coil (or Rx coil) 2911a can
be appropriately aligned. In some embodiments, the alignment
indicating unit may be a simple mark. In some embodiments, the
alignment indicating unit may be formed in a protruding structure
guiding the position of the electronic device (or Wireless power
receiver) 200. In some embodiments, the alignment indicating unit
may be formed with a magnetic material such as a magnet mounted
beneath the interface surface, so that the coils can be
appropriately aligned by attraction between the magnetic material
and another magnetic material with a different polarity, mounted in
the electronic device (or Wireless power receiver) 200.
[0106] Meanwhile, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may be formed to include one or
more transfer coils. The wireless power transfer apparatus (or
Wireless power transmitter) 100 can power transfer efficiency by
selectively using some of the coils, which are appropriately
aligned with the receiving coil (or Rx coil) 2911a of the
electronic device (or Wireless power receiver) 200. The wireless
power transfer apparatus (or Wireless power transmitter) 100
including the one or more transfer coils will be described with
reference to FIG. 5.
[0107] Hereinafter, configurations of the wireless power transfer
apparatus and the electronic device using the inductive coupling,
applicable in the embodiments of the present disclosure
[0108] FIGS. 4A and 4B are a block diagram illustrating portions of
the configurations of the wireless power transfer apparatus (or
Wireless power transmitter) 100 and the electronic device (or
Wireless power receiver) 200 using electromagnetic induction,
applicable in embodiments of the present disclosure. The
configuration of the power transmission unit 110 included in the
wireless power transfer apparatus (or Wireless power transmitter)
100 will be described with reference to FIG. 4A, and the
configuration of the power supply unit 230 included in the
electronic device (or Wireless power receiver) 200 will be
described with reference to FIG. 4B.
[0109] Referring to FIG. 4A, the power conversion unit 111 of the
wireless power transfer unit 100 may include a transfer coil (Tx
coil or transmitting coil) 1111a and an inverter 1112.
[0110] The transfer coil 111a, as described above, forms a magnetic
field corresponding to the wireless power signal according to the
change in current. In some embodiment, the transfer coil
(Transmitting coil or Tx coil) 1111a may be implemented as a planar
spiral type coil. In some embodiments, the transfer coil
(Transmitting coil or Tx coil) 1111a may be implemented as a
cylindrical solenoid type coil.
[0111] The inverter 1112 transforms a DC input obtained from the
power supply unit 190 to an AC waveform. The AC current transformed
by the inverter 112 drives a resonance circuit including the
transfer coil (Transmitting coil or Tx coil) 1111a and a capacitor
(not shown), so that a magnetic field is formed in the transfer
coil (Transmitting coil or Tx coil) 1111a. The wireless power
signal can be transmitted from the wireless power transfer
apparatus (or Wireless power transmitter) 100 to the wireless power
receiving apparatus (or Wireless power receiver) 200 due to the
formed magnetic field.
[0112] According to an embodiment, the AC waveform generated in the
inverter 1112 may be a carrier signal. The carrier signal drives
the resonance circuit, and the wireless power signal may be
generated from the transfer coil (Transmitting coil or Tx coil)
1111a by driving the resonance circuit. That is, the wireless power
signal may be formed based on the carrier signal.
[0113] The power conversion unit 111 may further include a
positioning unit 1114.
[0114] The positioning unit 1114 may move or rotate the transfer
coil (Transmitting coil or Tx coil) 1111a so as to improve the
efficiency of the wireless power transmission according to the
inductive coupling. This is because, as described above, the power
transmission according to the inductive coupling is influenced by
the alignment and distance between the wireless power transfer
apparatus (or Wireless power transmitter) 100 and the electronic
device (or Wireless power receiver) 200, which include the primary
and secondary coils, respectively. Particularly, the positioning
unit 1114 may be used when the electronic device (or Wireless power
receiver) 200 does not exist in the active area of the wireless
power transfer apparatus (or Wireless power transmitter) 100.
[0115] Therefore, the positioning unit 1114 may include a driving
unit (not shown). The driving unit moves the transfer coil
(Transmitting coil or Tx coil) 1111a so that the distance between
the centers of the transfer coil (Transmitting coil or Tx coil)
1111a of the wireless power transfer apparatus (or Wireless power
transmitter) 100 and the receiving coil (or Rx coil) 2911a of the
electronic device (or Wireless power receiver) 200 is within a
certain range, or rotates the transfer coil (Transmitting coil or
Tx coil) 1111a so that the centers of the transfer coil
(Transmitting coil or Tx coil) 1111a and the receiving coil (or Rx
coil) 2911a are overlapped with each other.
[0116] To this end, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may be further provided with a
position detection unit (not shown) including a sensor for sensing
the position of the electronic device (or Wireless power receiver)
200. The power transmission control unit 112 may control the
positioning unit 1114 based on information on the position of the
electronic device (or Wireless power receiver) 200, received from
the position detection sensor.
[0117] To this end, the power transmission control unit 112 may
receive control information on the alignment or distance between
the wireless power transfer apparatus (or Wireless power
transmitter) 100 and the electronic device (or Wireless power
receiver) 200 through the modulation/demodulation unit 113, and
control the positioning unit 1114 based on the received control
information on the alignment or distance.
[0118] If the power conversion unit 111 is configured to include a
plurality of transfer coils, the positioning unit 1114 may
determine which transfer coil is to be used for the purpose of
power transmission. The configuration of the wireless power
transfer apparatus (or Wireless power transmitter) 100 including
the plurality of transfer coils will be described later with
reference to FIG. 5.
[0119] Meanwhile, the power conversion unit 111 may further include
a power sensing unit 1115. The power sensing unit 1115 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 monitors current or voltage flowing through the transfer coil
(Transmitting coil or Tx coil) 1111a. The power sensing unit 1115
is used to identify whether or not the wireless power transfer
apparatus (or Wireless power transmitter) 100 normally operates.
The power sensing unit 1115 may detect voltage or current of power
supplied from the outside and identify whether or not the detected
voltage or current exceeds a critical value. Although not shown in
this figure, the power sensing unit 1115 may include a resistor for
detecting voltage or current of power supplied from the outside and
a comparator for comparing the detected voltage or current of the
power with a critical value and outputting the compared result. The
power transmission control unit 112 may cut off the power applied
to the transfer coil (Transmitting coil or Tx coil) 1111a by
controlling a switching unit (not shown), based on the compared
result output from the power sensing unit 1115.
[0120] Referring to FIG. 4B, the power supply unit 290 of the
electronic device (or Wireless power receiver) 200 may include a
receiving coil (Rx coil) 2911a and a rectifying circuit (or
rectifier circuit) 2913.
[0121] Current is induced in the receiving coil (or Rx coil) 2911a
by the change in the magnetic field formed from the transfer coil
(Transmitting coil or Tx coil) 1111a. Like the transfer coil
(Transmitting coil or Tx coil) 1111a, the receiving coil (or Rx
coil) 2911a may be implemented as a planar spiral type coil or
cylindrical solenoid type coil according to embodiments.
[0122] Series and parallel capacitors may be connected to the
receiving coil (or Rx coil) 2911a so as to improve the reception
efficiency of wireless power or to perform resonant detection.
[0123] The receiving coil (or Rx coil) 2911a may be implemented as
a single coil or a plurality of coils.
[0124] The rectifying circuit (or Rectifier circuit) 2913 performs
full-wave rectification on current so as to convert AC current into
DC current. The rectifying circuit (or Rectifier circuit) 2913 may
be implemented, for example, as a full bridge rectifying circuit
composed of four diodes or a circuit using active components.
[0125] The rectifying circuit (or Rectifier circuit) 2913 may
further include a smoothing circuit that allows the rectified
current to be a smoother and more stable DC current. The output
power of The rectifying circuit (or Rectifier circuit) 2913 is
supplied to each of the components of the power supply unit 290.
The rectifying circuit (or Rectifier circuit) 2913 may further
include a DC-DC converter that converts the output DC power into an
appropriate voltage suitable for power required in each of the
components (e.g., a circuit such as the charging unit 298) of the
power supply unit 290.
[0126] The modulation/demodulation unit 293 is connected to the
power receiving unit 291. The modulation/demodulation unit 293 may
be configured as a resistive element of which resistance is changed
with respect to DC current, or may be configured as a capacitive
element of which reactance is changed with respect to AC current.
The power receiving control unit 292 may modulate a wireless power
signal received to the power receiving unit 291 by changing
resistance or reactance of the modulation/demodulation unit
293.
[0127] Meanwhile, the power supply unit 290 may further include a
power sensing unit 2914. The power sensing unit 2914 of the
electronic device (or Wireless power receiver) 200 monitors voltage
and/or current of power rectified by The rectifying circuit (or
Rectifier circuit) 2913. When it is monitored that the voltage
and/or current of the rectified power exceeds a critical value, the
power receiving control unit 292 transfers a power control message
to the wireless power transfer apparatus (or Wireless power
transmitter) 100 so as to transmit appropriate power to the
wireless power transfer apparatus (or Wireless power transmitter)
100.
[0128] FIG. 5 is a block diagram of the wireless power transfer
apparatus configured to have one or more transfer coils for
receiving power according to the inductive coupling, applicable in
embodiments of the present disclosure.
[0129] Referring to FIG. 5, the power conversion unit 111 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 according to embodiments of the present disclosure may include
one or more transfer coils 1111a-1 to 1111a-n. The one or more
transfer coils 1111a-1 to 1111a-n may be an array of partially
overlapping primary coils. The active area may be determined by a
portion of the one or more transfer coils.
[0130] The one or more transfer coils 1111a-1 to 1111a-n may be
mounted beneath the interface surface. The power conversion unit
111 may further include a multiplexer 1113 that establishes or
removes connections between some of the one or more transfer coils
1111a-1 to 1111a-n.
[0131] If the position of the electronic device (or Wireless power
receiver) 200 placed on the interface surface is detected, the
power transmission control unit 112 may control the multiplexer
1113 so that some of the one or more transfer coils 1111a-1 to
1111a-n in an inductive coupling relationship with the receiving
coil (or Rx coil) 2911a can be connected, in consideration of the
detected position of the electronic device (or Wireless power
receiver) 200.
[0132] To this end, the power transmission control unit 112 may
obtain position information of the electronic device (or Wireless
power receiver) 200. In some embodiments, the power transmission
control unit 112 may obtain the position of the electronic device
(or Wireless power receiver) 200 on the interface surface using the
position detection unit (not shown) provided to the wireless power
transfer apparatus (or Wireless power transmitter) 100. In some
embodiments, the power transmission control unit 112 may obtain the
position of the electronic device (or Wireless power receiver) 200
by receiving a power control message indicating the intensity of a
wireless power signal from an object on the interface surface or a
power control message indicating identification information of the
object using each of the one or more transfer coils 1111a-1 to
1111a-n and then determining to which coil the object comes close
among the one or more transfer coils, based on the received
result.
[0133] Meanwhile, the active area is a portion of the interface
surface, and may mean a portion through which a high-efficiency
magnetic field can pass when the wireless power transfer apparatus
(or Wireless power transmitter) 100 transmits power by wireless to
the electronic device (or Wireless power receiver) 200. In this
case, a single transfer coil or a combination of one or more
transfer coils, which forms the magnetic field passing through the
active area, may be referred to as a primary cell. Therefore, the
power transmission control unit 112 may control the multiplexer
1113 so that coils belonging to the primary cell can be in the
inductive coupling relationship with the receiving coil (or Rx
coil) 2911a of the electronic device (or Wireless power receiver)
200 by determining the active area based on the detected position
of the electronic device (or Wireless power receiver) 200 and
establishing the connection of the primary cell corresponding to
the active area.
[0134] When one or more electronic devices 200 are placed on the
interface surface of the wireless power transfer apparatus (or
Wireless power transmitter) 100 configured to include the one or
more transfer coils 1111a-1 to 1111a-n, the power transmission
control unit 112 may control the multiplexer 1113 so that coils
belonging to the primary cell corresponding to the position of each
of the electronic devices 200 are in the inductive coupling
relationship. Accordingly, the wireless power transfer apparatus
(or Wireless power transmitter) 100 can transmit power by wireless
to the one or more electronic devices by respectively forming
wireless power signals using different coils.
[0135] The power transmission control unit 112 may control the
multiplexer 1113 to supply powers having different characteristics
to the respective coils corresponding to the electronic devices. In
this case, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may transmit power by configuring a power
transmission method, efficiency, characteristic, etc. for each of
the electronic devices. The power transmission for one or more
electronic devices will be described later with reference to FIG.
8.
[0136] Meanwhile, the power conversion unit 111 may further include
an impedance matching unit (not shown) that adjusts impedance so as
to form a resonant circuit with the connected coils.
[0137] Hereinafter, the method in which the wireless power transfer
apparatus transmits power according to embodiments supporting to
the electromagnetic resonance coupling will be described with
reference to FIGS. 6 to 8.
[0138] FIG. 6 illustrates a concept that power is transmitted by
wireless from the wireless power transfer apparatus to the
electronic device according to electromagnetic resonance
coupling.
[0139] First, resonance (or consonance) will be briefly described
as follows. The resonance refers to a phenomenon in which a
resonance system periodically receives an external force having the
same vibration frequency as the unique vibration frequency of the
resonance system so that the amplitude of vibration is distinctly
increased. The resonance is a phenomenon that occurs in all
vibrations including a dynamic vibration, an electrical vibration,
etc. Generally, if the unique vibration frequency of the resonance
system is identical to the vibration frequency of the external
force when the external force is applied to the resonance system,
the vibration of the resonance system grows harder, and the
amplitude of the vibration is also increased.
[0140] In the same principle, when a plurality of vibrating bodies
distant within a certain distance vibrate at the same frequency,
the plurality of vibrating bodies mutually resonate. In this case,
the resistance between the plurality of vibrating bodies is
decreased. In an electric circuit, a resonant circuit may be formed
using an inductor and a capacitor.
[0141] When the power transmission of the wireless power transfer
apparatus (or Wireless power transmitter) 100 is performed
according to the electromagnetic resonance coupling, a magnetic
field having a specific vibration frequency is formed by AC power
in the power transmission unit 110. When a resonance phenomenon is
caused by the formed magnetic field in the electronic device (or
Wireless power receiver) 200, power is generated by the resonance
phenomenon in the electronic device (or Wireless power receiver)
200.
[0142] The principle of the electromagnetic resonance coupling will
be described. In the method of generating an electromagnetic wave
and transferring power using the generated electromagnetic wave,
power transfer efficiency may be generally low.
[0143] However, if the plurality of vibrating bodies
electromagnetically resonate with one another as described above,
the plurality of vibrating bodies are not influenced by peripheral
objects, and hence the power transfer efficiency may be very high.
Therefore, an energy tunnel may be caused between the plurality of
vibrating bodies electromagnetically resonating with one another.
This is referred to as an energy coupling or energy tail.
[0144] The electromagnetic resonance coupling according to the
present disclosure may use an electromagnetic wave having a low
frequency. When power is transferred using the electromagnetic wave
having the low frequency, only a magnetic field has influence on an
area placed within a single wavelength of the electromagnetic wave.
This may be called as magnetic coupling or magnetic resonance. The
magnetic resonance may be caused when the wireless power transfer
apparatus (or Wireless power transmitter) 100 and the electronic
device (or Wireless power receiver) 200 are placed within the
single wavelength of the electromagnetic wave having the low
frequency.
[0145] The energy tail is formed by the resonance phenomenon, and
therefore, the power transfer has non-radioactive power transfer.
For this reason, it is possible to solve a radioactive problem that
may frequently occur when power is transferred using the
electromagnetic wave.
[0146] The electromagnetic resonance coupling may be a method of
transmitting power using an electromagnetic wave having a low
frequency as described above. Therefore, a transfer coil 1111b of
the wireless power transfer apparatus (or Wireless power
transmitter) 100 may generate a magnetic field or electromagnetic
wave for power transmission as a rule. However, the electromagnetic
resonance coupling, hereinafter, will be described in view of the
magnetic resonance, i.e., the power transmitted by the magnetic
field.
[0147] The resonance frequency may be determined, for example, by
the following Equation 1.
f = 1 2 .pi. LC Equation 1 ##EQU00001##
[0148] Here, the resonance frequency f is determined by inductance
L and capacitance C in a circuit. In a circuit forming a magnetic
field using coils, the inductance may be determined by the number
of turns of the coils, etc., and the capacitance may be determined
by the interval between the coils, the area of the coils, etc. To
determine the resonance frequency, the circuit may be configured so
that a capacitive resonant circuit as well as the coils is
connected to the circuit.
[0149] Referring to FIG. 6, in embodiments in which power is
transferred by wireless according to the electromagnetic resonance
coupling, the power conversion unit 111 of the wireless power
transfer apparatus (or Wireless power transmitter) 100 may be
configured to include a transfer coil (Tx coil) 1111b in which a
magnetic field is formed and a resonance generation circuit 1116
for determining a specific vibration frequency. The resonance
generation circuit 1116 may be implemented using a capacitive
circuit, and the specific vibration frequency is determined based
on the inductance of the transfer coil 1111b and the capacitance of
the resonance generation circuit 1116.
[0150] The configuration of circuit elements in the resonance
generation unit 1116 may be implemented in various forms so that
the power conversion unit 111 can form a magnetic field. The
configuration is not limited to that in which the power conversion
unit 111 is connected in parallel to the transfer coil 1111b as
shown in FIG. 6.
[0151] The power receiving unit 291 of the electronic device (or
Wireless power receiver) 200 includes a resonance generation
circuit 2912 and a receiving coil (Rx coil) 2911b, configured so
that the resonance phenomenon is caused by the magnetic field
formed in the wireless power transfer apparatus (or Wireless power
transmitter) 100. That is, the resonance generation circuit 2912
may also implemented using a capacitive circuit. The resonance
generation circuit 2912 is configured so that the resonance
frequency determined based on the inductance of the receiving coil
2911b and the capacitance of the resonance generation circuit 2912
is identical to that of the formed magnetic field.
[0152] The configuration of circuit elements in the resonance
generation circuit 2912 may be implemented in various forms so that
resonance can be generated by the magnetic field in the power
receiving unit 291. The configuration is not limited to that in
which the power receiving unit 291 is connected in series to the
receiving coil 2911b as shown in FIG. 6.
[0153] The specific resonance frequency in the wireless power
transfer apparatus (or Wireless power transmitter) 100 has LTx and
CTx, and can be obtained using Equation 1. Here, resonance is
generated in the electronic device (or Wireless power receiver) 200
when the result obtained by substituting LRX and CRX of the
electronic device (or Wireless power receiver) 200 into Equation 1
is identical to the specific vibration frequency.
[0154] According to the embodiments supporting the wireless power
transfer using the electromagnetic resonance coupling, when the
wireless power transfer apparatus (or Wireless power transmitter)
100 and the electronic device (or Wireless power receiver) 200
resonate at the same frequency, the electromagnetic wave is
transmitted through a short-range electromagnetic field. Therefore,
if the resonance frequencies are different from each other, there
is not energy transmission between devices.
[0155] Accordingly, the efficiency of the wireless power
transmission using the electromagnetic resonance coupling is
considerably influenced by properties of frequencies. On the other
hand, the efficiency of the wireless power transmission using the
electromagnetic resonance coupling is relatively less influenced by
the alignment and distance between the wireless power transfer
apparatus (or Wireless power transmitter) 100 and the electronic
device (or Wireless power receiver) 200, which include the
respective coils, as compared with the inductive coupling.
[0156] Hereinafter, the configuration of the wireless power
transfer apparatus and the electronic device using the
electromagnetic resonance coupling, applicable in embodiments of
the present disclosure will be described in detail.
[0157] FIGS. 7A and 7B are a block diagram illustrating portions of
the configurations of the wireless power transfer apparatus (or
Wireless power transmitter) 100 and the electronic device (or
Wireless power receiver) 200 using the electromagnetic resonance
coupling, applicable in embodiments of the present disclosure.
[0158] The configuration of the power transmission unit 110
included in the wireless power transfer apparatus (or Wireless
power transmitter) 100 will be described with reference to FIG.
7A.
[0159] The power conversion unit 111 of the wireless power transfer
apparatus (or Wireless power transmitter) 100 may include a
transfer coil (Tx coil) 1111b, an inverter 1112 and a resonance
generation circuit 1116. The inverter 1112 may be connected to the
transfer coil 1111b and the resonance generation circuit 1116.
[0160] The transfer coil 1111b may be mounted separately from the
transfer coil (Transmitting coil or Tx coil) 1111a for transmitting
power according to the inductive coupling, but may transmit power
using a single coil according to the inductive coupling and the
electromagnetic resonance coupling.
[0161] The transfer coil 1111b, as described above, forms a
magnetic field for transmitting power. If AC power is applied, the
transfer coil 1111b and the resonance generation circuit 1116
generate a vibration. In this case, the vibration frequency may be
determined based on the inductance of the transfer coil 1111b and
the capacitance of the resonance generation circuit 1116.
[0162] To this end, the inverter 11112 transforms a DC input
obtained from the power supply unit 190 to an AC waveform, and the
transformed AC current is applied to the transfer coil 1111b and
the resonance generation circuit 1116.
[0163] In addition, the power conversion unit 111 may further
include a frequency regulation unit (or frequency adjustment unit)
1117 for changing the resonance frequency of the power conversion
unit 111. Since the resonance frequency of the power conversion
unit 111 is determined based on inductance and capacitance in a
circuit constituting the power conversion unit 111 using Equation
1, the power transmission control unit 112 controls the frequency
regulation unit 1117 to change the inductance and/or the
capacitance, thereby determining the resonance frequency of the
power conversion unit 111.
[0164] In some embodiments, the frequency regulation unit 1117 may
include a motor capable of changing capacitance by regulating a
distance between capacitors included in the resonance generation
circuit 1116. In some embodiments, the frequency regulation unit
1117 may include a motor capable of changing inductance by
regulating the number of turns or diameter of the transfer coil
1111b. In some embodiments, the frequency regulation unit 1117 may
include active elements for determining the capacitance and/or the
inductance.
[0165] Meanwhile, the power conversion unit 111 may further include
a power sensing unit 1115. The operation of the power sensing unit
1115 is the same as described above.
[0166] The configuration of the power supply unit 290 included in
the electronic device (or Wireless power receiver) 200 will be
described with reference to FIG. 7B. The power supply unit 290, as
described above, may include the receiving coil (Rx coil) 2911b and
the resonance generation circuit 2912.
[0167] In addition, the power receiving unit 291 of the power
supply unit 290 may further include a rectifying circuit 2913 that
converts AC current generated by the resonance phenomenon into DC
current. The rectifying circuit (or Rectifier circuit) 2913 may be
configured the same as described above.
[0168] The power receiving unit 291 may further include a frequency
regulation unit 2917 for changing a resonance frequency of the
power receiving unit 291. Since the resonance frequency of the
power receiving unit 291 is determined based on inductance and
capacitance in a circuit constituting the power receiving unit 291
using Equation 1, the power receiving control unit 292 controls the
frequency regulation unit 2917 to change the inductance and/or the
capacitance, thereby determining the resonance frequency of the
power receiving unit 291.
[0169] In some embodiments, the frequency regulation unit 2917 may
include a motor capable of changing capacitance by regulating a
distance between capacitors included in the resonance generation
circuit 2912. In some embodiments, the frequency regulation unit
2917 may include a motor capable of changing inductance by
regulating the number of turns or diameter of the transfer coil
2911b. In some embodiments, the frequency regulation unit 2917 may
include active elements for determining the capacitance and/or the
inductance.
[0170] The power receiving unit 291 may further include a power
sensing unit 2914 that monitors voltage and/or current of rectified
power. The power sensing unit 2914 may be configured the same as
described above.
[0171] FIG. 8 is a block diagram of the wireless power transfer
apparatus configured to have one or more transfer coils for
receiving power according to the electromagnetic resonance
coupling, applicable in embodiments of the present disclosure.
[0172] Referring to FIG. 8, the power conversion unit 111 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 according to the embodiments of the present disclosure may
include one or more transfer coils 1111b-1 to 1111b-n and resonance
generation circuits 1116-1 to 1116-n respectively connected to the
transfer coils 1111b-1 to 1111b-n. The power conversion unit 111
may further include a multiplexer 1113 that establishes or removes
connections between some of the one or more transfer coils 1111b-1
to 1111b-n.
[0173] The one or more transfer coils 1111b-1 to 1111b-n may be
configured to have the same resonance frequency. In some
embodiments, some of the one or more transfer coils 1111b-1 to
1111b-n may be configured to have different resonance frequencies,
which is determined according to which inductance and/or
capacitance the resonance generation circuits 1116-1 to 1116-n
respectively connected to the transfer coils 1111b-1 to 1111b-n
have.
[0174] Meanwhile, when one or more electronic devices 200 are
displaced in the active area or semi-active area of the wireless
power transfer apparatus (or Wireless power transmitter) 100
configured to include the one or more transfer coils 1111b-1 to
1111b-n, the power transmission control unit 112 may control the
multiplexer 1113 so as to be in a different resonance coupling
relationship for each of the electronic devices. Accordingly, the
wireless power transfer apparatus (or Wireless power transmitter)
100 wireless power signals using the respective coils, so that
power can be transmitted by wireless to the one or more electronic
devices.
[0175] The power transmission control unit 112 may control the
multiplexer 1113 to supply powers having different characteristics
to the respective coils corresponding to the electronic devices. In
this case, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may transmit power by configuring a power
transmission method, efficiency, characteristic, etc. for each of
the electronic devices. The power transmission for one or more
electronic devices will be described later with reference to FIG.
28.
[0176] To this end, the frequency regulation unit 1117 may be
configured to change the inductance and/or capacitance of the
resonance generation circuits 1116-1 to 1116-n respectively
connected to the transfer coils 1111b-1 to 1111b-n.
[0177] Hereinafter, an example of the wireless power transfer
apparatus implemented in the form of a wireless charger will be
described.
[0178] FIG. 9 is a block diagram of the wireless power transfer
apparatus further including additional components except the
components shown in FIG. 2A.
[0179] As can be seen with reference to FIG. 9, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may further
include a sensor unit 120, a communication unit 130, an output unit
140, a memory 150 and a control unit (or Controller) 180, in
addition to the power transmission unit 110 and the power supply
unit 190, which support one or more of the inductive coupling and
the electromagnetic resonance coupling.
[0180] The control unit (or Controller) 180 controls the power
transmission unit 110, the sensor unit 120, the communication unit
130, the output unit 140, the memory 150 and the power supply unit
190.
[0181] The control unit (or Controller) 180 may be implemented as a
module separate from the power transmission control unit 112 in the
power transmission unit 110 described with reference to FIG. 2 or
may be implemented as a single module.
[0182] The sensor unit 120 may include a sensor that senses the
position of the electronic device (or Wireless power receiver) 200.
Information on the position sensed by the sensor unit 120 may be
used so that the power transmission unit 110 can efficiently
transmit power.
[0183] For example, in the wireless power transmission according to
the embodiments supporting the inductive coupling, the sensor unit
120 may operate as a position detection unit. The information on
the position sensed by the sensor unit 120 may be used to move or
rotate the transfer coil (Transmitting coil or Tx coil) 1111a in
the power conversion unit 111.
[0184] For example, the wireless power transfer apparatus (or
Wireless power transmitter) 100 according to the embodiments
configured to the one or more transfer coils described above may
determine coils, among the one or more transfer coils, which may be
in the inductive coupling relationship or electromagnetic resonance
coupling relationship with the receiving coil of the electronic
device.
[0185] Meanwhile, the sensor unit 120 may be configured to monitor
whether or not the electronic device (or Wireless power receiver)
200 comes close to an area in which charging is possible. The
function of sensing whether or not the sensor unit 120 comes close
may be performed separately from or combined with the function that
the power transmission control unit 112 in the power transmission
unit 110 senses whether or not the electronic device comes
close.
[0186] The communication unit 130 performs wire/wireless data
communication with the electronic device (or Wireless power
receiver) 200. The communication unit 130 may include electronic
components for one or more of Bluetooth.TM., Zigbee, ultra wide
band (UWB), wireless USB, near field communication (NFC) and
wireless LAN.
[0187] The output unit 140 includes at least one of a display unit
141 and a sound output unit (or Audio output unit) 142. The display
unit 141 may include at least one of a liquid crystal display
(LCD), a thin film transistor-liquid crystal display (TFT LCD), an
organic light-emitting diode (OLED), a flexible display and a 3D
display. The display unit 141 may display a charging state under a
control of the control unit (or Controller) 180.
[0188] The memory 150 may include a storage medium of at least one
of a flash memory type, a hard disk type, a multimedia card micro
type, a card type memory (e.g., an SD or XD memory, etc.), a random
access memory (RAM), a static random access memory (SRAM), a
read-only memory (ROM), an electrically erasable programmable
read-only memory (EEPROM), a programmable read-only memory (PROM),
a magnetic memory, a magnetic disk and an optic disk. The wireless
power transfer apparatus (or Wireless power transmitter) 100.
Programs or commands executing the aforementioned functions of the
wireless power transfer apparatus (or Wireless power transmitter)
100 may be stored in the memory 150. The control unit (or
Controller) 180 may execute the programs or commands stored in the
memory 150 so as to transfer power by wireless. A memory controller
(not shown) may be used so that other components (e.g., the control
unit (or Controller) 180) included in the wireless power transfer
apparatus (or Wireless power transmitter) 100 access the memory
150.
[0189] It will be readily understood by those skilled in the art
that the configuration of the wireless power transfer apparatus
according to the embodiments of the present disclosure may be
applied to devices such as a docking station, a terminal cradle
device and other electronic devices, except that the configuration
of the wireless power transfer apparatus is applicable to only the
wireless charger.
[0190] FIG. 10 is illustrates a configuration of the electronic
device (or Wireless power receiver) 200 implemented in the form of
a mobile terminal according to embodiments of the present
disclosure.
[0191] The mobile terminal 200 includes the power supply unit 290
shown in FIG. 2, 4 or 7.
[0192] The mobile terminal 200 may further include a wireless
communication unit 210, audio/video (A/V) input unit 220, a user
input unit 230, a sensing unit 240, an output unit 250, a memory
260, an interface unit 270 and a control unit 280. The components
shown in FIG. 10 are not essential, and therefore, the mobile
terminal may be implemented to have a larger number of components
or to have a smaller number of components.
[0193] Hereinafter, the components will be sequentially
described.
[0194] The wireless communication unit 210 may include one or more
modules that enable wireless communication between the mobile
terminal 200 and a wireless communication system, between the
mobile terminal 200 and a network in which the mobile terminal 200
is placed, or between the mobile terminal 200 and the wireless
power transfer apparatus (or Wireless power transmitter) 100. For
example, the wireless communication unit 210 may include a
broadcast receiving module 211, a mobile communication module 212,
a wireless Internet module 213, a short range communication module
214, a position information module (LOCATION INFORMATION MODULE or
position-location MODULE) 215, etc.
[0195] The broadcast receiving module 211 receives a broadcasting
signal and/or broadcasting related information from an external
broadcasting center through a broadcasting channel.
[0196] The broadcasting channel may include a satellite channel and
a terrestrial channel. The broadcasting center may mean a server
that generates a broadcasting signal and/or broadcasting related
information and transfers the generated broadcasting signal and/or
broadcasting related information to the mobile terminal or a server
that receives a previously generated broadcasting signal and/or
broadcasting related information and transfer the received
broadcasting signal and/or broadcasting related information to the
mobile terminal. The broadcasting signal may include not only a TV
broadcasting signal, a radio broadcasting signal and a data
broadcasting signal but also a broadcasting signal obtained by
combining the data broadcasting signal with the TV broadcasting
signal or radio broadcasting signal.
[0197] The broadcasting related information may mean information
related to a broadcasting channel, broadcasting program or
broadcasting service provider. The broadcasting related information
may be provided through a mobile communication network. In this
case, the broadcasting related information may be received by the
mobile communication module 212.
[0198] The broadcasting related information may exist in various
forms. For example, the broadcasting related information may exist
in the form of an electronic program guide (EPG) of digital
multimedia broadcasting (DMB), electronic service guide (ESG) of
digital broadcast-handheld (DVB-H), etc.
[0199] The broadcast receiving module 211 may receive a digital
broadcasting signal, for example, using a digital broadcasting
system such as digital multimedia broadcasting-terrestrial (DMB-T),
digital multimedia broadcasting-satellite (DMB-S), media forward
link only (MediaFLO), digital video broadcasting-handheld (DVB-H)
or integrated service digital broadcast-terrestrial (ISDB-T). It
will be apparent that the broadcast receiving module 211 may be
configured to be suitable for not only the digital broadcasting
system but also another broadcasting system.
[0200] The broadcasting signal and/or the broadcasting related
information received through the broadcast receiving module 211 may
be stored in the memory 260.
[0201] The mobile communication module 212 transmits/receives a
wireless signal with at least one of a base station, an external
terminal and a server on the mobile communication network. The
wireless signal may include a voice call signal, a video call
signal and various types of data according to character/multimedia
message transmission/reception.
[0202] The wireless Internet module 213 refers to a module for
wireless Internet access, and may be built in the mobile terminal
200 or mounted to the outside of the mobile terminal 200. The
wireless Internet access may include wireless LAN (Wi-Fi), wireless
broadband (Wibro), world interoperability for microwave access
(Wimax), high speed downlink packet access (HSDPA), etc.
[0203] The short range communication module 214 refers to a module
for short range communication. The wireless short range
communication may include Bluetooth, radio frequency identification
(RFID), infrared data association (IrDA), ZigBee, etc. Meanwhile,
the wired short range communication may include universal serial
bus (USB), IEEE 1394, Thunderbolt.TM., etc.
[0204] The wireless Internet module 213 or the short range
communication module 214 may establish data communication
connection with the wireless power transfer apparatus (or Wireless
power transmitter) 100.
[0205] When there exists an audio signal to be output while
transmitting power by wireless through the established data
communication, the wireless Internet module 213 or the short range
communication module 214 may transfer the audio signal to the
wireless power transfer apparatus (or Wireless power transmitter)
100 through the short range communication module. When there exists
information to be displayed through the established data
communication, the wireless Internet module 213 or the short range
communication module 214 may transfer the information to the
wireless power transfer apparatus (or Wireless power transmitter)
100. Alternatively, the wireless Internet module 213 or the short
range communication module 214 may receive an audio signal input
through a microphone built in the wireless power transfer apparatus
(or Wireless power transmitter) 100 through the established data
communication. The wireless Internet module 213 or the short range
communication module 214 may transfer identification information
(e.g., a phone number or device name in a cellular phone) of the
mobile terminal 200 to the wireless power transfer apparatus (or
Wireless power transmitter) 100 through the established data
communication.
[0206] The position information module (LOCATION INFORMATION MODULE
or position-location MODULE) 215 refers to a module for obtaining
the position of the mobile terminal, and a global positioning
system (GPS) module may be used as an example of the position
information module (LOCATION INFORMATION MODULE or
position-location MODULE) 215.
[0207] Referring to FIG. 10, the A/V input unit 220 is used to
input an audio or video signal, and may include a camera 221, a
microphone 222, etc. The camera 221 processes an image frame such
as a still image or moving image obtained by an image sensor in a
video call mode or photographing mode. The processed image frame
may be displayed in the display unit 251.
[0208] The image frame processed in the camera 221 may be stored in
the memory 260 or may be transferred to the outside through the
wireless communication unit 210. The camera 221 may be provided
with two or more cameras according to the environment used.
[0209] The microphone 222 receives an external sound signal in a
call mode, recording mode, voice recognition mode, etc., and
processes the received sound signal as voice data. The processed
voice data may be converted and output to be transferred to a
mobile communication station through the mobile communication
module 212 in the call mode. Various noise removing algorithms for
removing noise generated in the process of receiving an external
sound signal may be implemented in the microphone 222.
[0210] The user input unit 230 generates input data for controlling
the operation of a user terminal. The user input unit 230 may be
configured as a key pad, dome switch, touch pad (static
voltage/static current), a jog wheel, jog switch, etc.
[0211] The sensing unit 240 may include a proximity sensor 241, a
pressure sensor, a motion sensor 243, etc. The proximity sensor 241
may detect, without any mechanical contact, an object approaching
the mobile terminal 200, an object existing in the vicinity of the
mobile terminal 200, etc. The proximity sensor 241 may detect an
object approaching the mobile terminal 200 using a change in AC
magnetic field or static magnetic field, a change in capacitance,
etc. The proximity sensor 241 may be provided with two or more
proximity sensors according to the environment used.
[0212] The pressure sensor 242 may detect whether or not pressure
is applied to the mobile terminal 200, the strength of the
pressure, etc. The pressure sensor 242 may be mounted at a portion
necessary for detection of pressure in the mobile terminal 200
according to the environment used. If the pressure sensor 242 is
mounted in the display unit 251, the pressure sensor 242 may
identify a touch input through the display unit 251 and a pressure
touch input of which pressure is greater than that of the touch
input, according to the signal output from the pressure sensor 242.
The pressure sensor 242 may detect the strength of the pressure
applied to the display unit 251 when a pressure touch is input,
according to the signal output from the pressure sensor 242.
[0213] The motion sensor 243 senses a position or motion of the
mobile terminal 200 using an acceleration sensor, gyro sensor, etc.
The acceleration sensor used for the motion sensor 243 is an
element that changes a change in acceleration in any one direction
into an electrical signal. The acceleration sensor is generally
configured by mounting two or three axes in one package, and may
require only one axis, i.e., the Z-axis according to the
environment used. Therefore, when an acceleration sensor in the
direction of the X- or Y-axis is used other than that in the
direction of the Z-axis, the acceleration sensor may be mounted
vertically to a main board using a separate piece of board. The
gyro sensor is a sensor that measures an angular speed of the
mobile terminal 200 performing a rotary motion, and may sense an
angle at which the mobile terminal 200 is rotated with respect to
each reference direction. For example, the gyro sensor may sense
rotational angles, i.e., an azimuth, a pitch and a roll, with
respect to the three directional axes.
[0214] The output unit 250 is used to generate an output related to
a visual sense, auditory sense, a haptic sense, etc. The output
unit 250 may include a display unit 251, a sound output module (or
AUDIO OUTPUT MODULE) 252, an alarm unit 253, a haptic module 254,
etc.
[0215] The display unit 251 displays (outputs) information
processed in the mobile terminal 200. For example, when the mobile
terminal 200 is in a call mode, the display unit 251 displays a
user interface (UI) or graphic user interface (GUI) related to a
call. When the mobile terminal 200 is in a video call mode or
photographing mode, the display unit 251 displays a photographed
or/and received image, UI or GUI.
[0216] The display unit 251 may include at least one of an LCD, a
TFT LCD, an OLED, a flexible display and a 3D display.
[0217] Some of these displays may be configured as transparent or
light-transmissive displays through which a user can see an outside
view. These displays may be called as transparent displays, and
transparent OLED, etc. may be used as a representative of the
transparent displays. The rear structure of the display unit 251
may also be configured as a light-transmissive structure. Through
such a structure, the user can see an object positioned at the rear
of the mobile terminal 200 through an area occupied by the display
unit 251 of the mobile terminal 200.
[0218] Two or more display units 251 may exist according to the
implemented form of the mobile terminal 200. For example, a
plurality of display units may be spaced apart or integrally
displaced on one surface, or may be displaced on different
surfaces, respectively.
[0219] When the display unit 251 and a sensor sensing a touch
operation (hereinafter, referred to as a `touch sensor`) form an
inter-layer structure (hereinafter, referred to as a `touch
screen`), the display unit 251 may be used as an input device as
well as an output device. The touch sensor may have, for example,
the form of a touch film, touch sheet, touch pad, etc.
[0220] The touch sensor may be configured to convert a change in
pressure applied to a specific portion of the display unit 251 or
capacitance generated at a specific portion of the display unit 251
into an electrical input signal. The touch sensor may be configured
to detect not only the position and area of a touched portion but
also the pressure at the touched portion.
[0221] When there is a touch input for the touch sensor, a signal
(s) corresponding to the touch input is sent to a touch controller.
The touch controller processes the signal (s) and then transfers
corresponding data to the control unit 280. Accordingly, the
control unit 280 can determine which area of the display unit 251
is touched, etc.
[0222] The proximity sensor 241 may be placed in an internal area
of the mobile terminal surrounded by the touch screen or in the
proximity of the touch screen. The proximity sensor 241 refers to a
sensor that senses, without any mechanical contact, an object
approaching a predetermined detection surface or the presence of
existence of an object existing near the predetermined detection
surface using an electromagnetic force or infrared ray.
[0223] For example, the proximity sensor 241 includes a
transmissive photoelectric sensor, a mirror reflective
photoelectric sensor, a high-frequency oscillation proximity
sensor, a capacitive proximity sensor, a magnetic proximity sensor,
an infrared proximity sensor, etc. When the touch screen is a
capacitive touch screen, the touch screen is configured to detect
the proximity of a pointer through a change in electric field
according the proximity of the pointer. In this case, the touch
screen (touch sensor) may be classified as the proximity
sensor.
[0224] Hereinafter, for convenience of illustration, the action
that the pointer comes close to the touch screen while not being
contacted on the touch screen so as to be recognized that the
pointer is placed on the touch screen is referred to as a
"proximity touch," and the action that the pointer is substantially
contacted on the touch screen is referred to as a "contact touch."
The position at which the pointer is proximately touched on the
touch screen means a position at which when the pointer is
proximately touched, the pointer corresponds vertically to the
touch screen.
[0225] The proximity sensor 241 senses a proximity touch action and
a proximity touch pattern (e.g., a proximity touch distance,
proximity touch direction, proximity touch speed, a proximity touch
time, proximity touch position, proximity touch movement state,
etc.). Information corresponding to the sensed proximity touch
action and proximity touch pattern may be output on the touch
screen.
[0226] The sound output module (or AUDIO OUTPUT MODULE) 252 may
receive a call signal from the wireless communication unit 210 in a
call or recoding mode, voice recognition mode, broadcast receiving
mode, etc., and may output the audio data stored in the memory 260.
The sound output module (or AUDIO OUTPUT MODULE) 252 may output a
sound signal related to a function (e.g., a call signal receiving
sound, message receiving sound, etc.) performed by the mobile
terminal 200. The sound output module (or AUDIO OUTPUT MODULE) 252
may include a receiver, a speaker, a buzzer, etc.
[0227] The alarm unit 253 outputs a signal for informing that an
event occurs in the mobile terminal 200. The event occurring in the
mobile terminal 200 includes, for example, call signal reception,
message reception, key signal input, touch input, etc. The alarm
unit 253 may output, for example, a signal for informing the
occurrence of an event through vibration, as well as a video or
audio signal. Since the video or audio signal may be output through
the display unit 251 or the sound output module (or AUDIO OUTPUT
MODULE) 252, the display unit 251 and the sound output module (or
AUDIO OUTPUT MODULE) 252 may be classified as a portion of the
alarm unit 253.
[0228] The haptic module 254 generates various haptic effects that
a user can feel. A vibration is used as a representative of the
haptic effects generated by the haptic module 254. The intensity
and pattern of the vibration generated by the haptic module 254 may
be controlled. For example, different vibrations may be synthesized
and output or may be sequentially output.
[0229] In addition to the vibration, the haptic module 254 may
generate various haptic effects including an effect caused by the
arrangement of pins performing a vertical movement on a contact
skin surface, an effect caused by the jet force or absorption force
of air through an absorption port, an effect caused by the graze
through a skin surface, an effect caused by the contact of an
electrode, an effect caused by a stimulus such as an electrostatic
force, an effect caused by the reproduction of a cool and warm
feeling using an element for heat absorption or generation,
etc.
[0230] The haptic module 254 may be implemented not only to provide
a user with a haptic effect through a direct contact but also to
allow the user to feel a haptic effect through a muscle sense using
a finger, arm, etc. The haptic module 254 may be provided with two
or more haptic modules according to the environment used.
[0231] The memory 260 may store a program for operations of the
control unit 280, and may temporarily store input/output data
(e.g., a phone book, a message, a still image, a moving image,
etc.). The memory 260 may store data for vibration and sound of
various patterns, which are output when a touch is input on the
touch screen.
[0232] In some embodiments, the memory 260 may store software
components including an operating system (not shown), a module
performing the function of wireless communication unit 210, a
module operating together with the user input unit 230, a module
operating together with the A/V input unit 220 and a module
operating together with the output module 250. The operating system
(e.g., LINUX, UNIX, OS X, WINDOWS, Chrome, Symbian, iOS, Android,
VxWorks or another embedded operating system) may include various
software components and/or drivers for controlling system tasks
such as memory management and power management.
[0233] The memory 260 may store a configuration program related to
wireless power transfer or wireless charging. The configuration
program may be executed by the control unit 280.
[0234] The memory 260 may store an application related to the
wireless power transfer (or wireless charging) downloaded from an
application providing server (e.g., an App store). The application
related to the wireless power transfer is a program for controlling
the wireless power transfer. The electronic device (or Wireless
power receiver) 200 may receive power by wireless from the wireless
power transfer apparatus (or Wireless power transmitter) 100
through the corresponding program or may establish connection for
data communication with the wireless power transfer apparatus (or
Wireless power transmitter) 100.
[0235] The memory 260 may include a storage medium of at least one
of a flash memory type, a hard disk type, a multimedia card micro
type, a card type memory (e.g., an SD or XD memory, etc.), a RAM,
an SRAM, a ROM, an EEPROM, a PROM, a magnetic memory, a magnetic
disk and an optic disk. The mobile terminal 200 may operate in
relation to a web storage performing a storage function of the
memory 260 on the Internet.
[0236] The interface unit 270 serves as a gateway to all external
devices connected to the mobile terminal 200. The interface unit
270 may receive data from an external device, may receive power and
provide the received power to each of the components in the mobile
terminal 200, or may allow data in the mobile terminal 200 to be
transmitted to the external device. For example, the interface unit
270 may include a wired/wireless headset port, an external charger
port, a wired/wireless data port, a memory card port, a port for
connecting an apparatus provided with an identification module, an
audio input/output (I/O) port, a video I/O port, an earphone port,
etc.
[0237] The identification module is a chip in which various
information for authenticating the use right of the mobile terminal
200, and may include a user identify module (UIM), a subscriber
identity module (SIM), a universal subscriber identity module USIM,
etc. The apparatus provided with the identification module
(hereinafter, referred to as an `identification apparatus`) may be
manufactured in the form of a smart card. Therefore, the
identification apparatus may be connected to the mobile terminal
200 through a port.
[0238] When the mobile terminal 200 is connected to an external
cradle, the interface unit 270 may become a path along which power
is supplied from the cradle to the mobile terminal 200, or may
become a path along which various command signals input from the
cradle are provided to the mobile terminal 200. The power or
various command signals input from the cradle may be operated as a
signal for recognizing that the mobile terminal 200 has been
exactly mounted to the cradle.
[0239] The control unit 280 generally controls overall operations
of the mobile terminal 200. For example, the control unit 280
performs relative control and processing for voice conversation,
data communication, video conversation, etc. The control unit 280
may have a multimedia module 281 for multimedia reproduction. The
multimedia module 281 may be implemented in the control unit 280 or
may be implemented separately from the control unit 280. The
control unit 280 may be implemented as a module separate from the
power receiving control unit 292 in the power supply unit 290
described with reference to FIG. 2, or may be implemented as a
single module.
[0240] The control unit 280 may perform pattern recognition
processing so that a writing or drawing input performed on the
touch screen can be recognized as a character or image.
[0241] The control unit 280 performs a wire or wireless charging
operation according to a user input or internal input. The internal
input is a signal for informing that inductive current generated in
the secondary coil of the mobile terminal has been sensed.
[0242] The operation in which the control unit 280 controls each of
the components when the wireless charging operation is performed
will be described in detail with reference to operational states of
FIG. 14. As described above, the power receiving control unit 292
in the power supply unit 290 may be implemented in the state in
which the power receiving control unit 292 is included in the
control unit 280. In this specification, it will be understood that
the operation of the power receiving control unit 292 is performed
by the control unit 280.
[0243] The power supply unit 290 receives external power and/or
internal power under a control of the control unit 280 so as to
supply power necessary for the operation of each of the
components.
[0244] The power supply unit 290 has a battery 299 supplying power
to each of the components in the mobile terminal 200. The power
supply unit 290 may include a charging unit 298 for charging the
battery 299 by wire or wireless.
[0245] The present disclosure has disclosed the mobile terminal as
the wireless power receiving apparatus. However, it can be readily
understood by those skilled in the art that the configuration
according to the embodiments of the present disclosure may be
applied to a fixed terminal such as a digital TV or desktop
computer, except a case in which the configuration according to the
embodiments of the present disclosure is applicable to only the
mobile terminal.
[0246] FIGS. 11A and 11B illustrate a concept that packets are
transmitted/received between the wireless power transfer apparatus
and the electronic device through modulation and demodulation of a
wireless power signal in wireless power transmission.
[0247] Referring to FIG. 11A, the wireless power signal generated
by the power conversion unit 111 forms a closed-loop in a magnetic
field or electromagnetic field. Therefore, when the wireless power
signal is modulated while the electronic device (or Wireless power
receiver) 200 receives the wireless power signal, the wireless
power transfer apparatus (or Wireless power transmitter) 100 may
detect the modulated wireless power signal. The
modulation/demodulation unit 113 may demodulate the detected
wireless power signal and decodes the packet from the demodulated
wireless power signal.
[0248] Meanwhile, the modulation method used in communication
between the wireless power transfer apparatus (or Wireless power
transmitter) 100 and the electronic device (or Wireless power
receiver) 200 may be an amplitude modulation method. As described
above, the amplitude modulation method may be a backscatter
modulation method in which the modulation/demodulation unit 293 of
the electronic device (or Wireless power receiver) 200 modulates
the amplitude of a wireless power signal 10a generated by the power
conversion unit 111 and the modulation/demodulation unit 113 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 then detects the amplitude of the modulated wireless power
signal 10b.
[0249] Specifically, referring to FIG. 11B, the power receiving
control unit 292 of the electronic device (or Wireless power
receiver) 200 modulates the wireless power signal 10a received
through the power receiving unit 291 by changing load impedance in
the modulation/demodulation unit 293. The power receiving control
unit 292 modulates the wireless power signal 10a so that the packet
containing a power control message to be transferred to the
wireless power transfer apparatus (or Wireless power transmitter)
100 is included in the wireless power signal 10a.
[0250] Then, the power transmission control unit 112 of the
wireless power transfer apparatus (or Wireless power transmitter)
100 demodulates the modulated wireless power signal 10b through an
envelope detection process, and decodes the detected signal 10c
into digital data 10d. The demodulation process is a process of
detecting that current or voltage flowing through the power
conversion unit 111 is divided into two phases, i.e., HI and LO
phases by the modulated wireless power signal and obtaining the
packet that the electronic device (or Wireless power receiver) 200
intends to transfer based on digital data divided according to the
phases.
[0251] Hereinafter, a process in which the wireless power transfer
apparatus (or Wireless power transmitter) 100 obtains a power
control message that the electronic device (or Wireless power
receiver) 200 intends to transfer from demodulated digital data
will be described.
[0252] FIGS. 12A and 12B illustrates a method in which the wireless
power transfer apparatus (or Wireless power transmitter) 100
displays data bits and bytes constituting a power control
message.
[0253] Referring to FIG. 12A, the power transmission control unit
detects bits encoded using a clock signal CLK from a signal of
which envelope is detected. The encoded bits detected by the power
transmission control unit 112 are encoded using a bit encoding
method used in the modulation process of the electronic device (or
Wireless power receiver) 200. In some embodiments, the bit encoding
method may be non-return to zero (NRZ). In some embodiments, the
bit encoding method may be a bi-phase encoding method.
[0254] For example, in some embodiments, the detected bits may be
bits encoded using differential bi-phase (DBP) encoding. According
to the DBP encoding, the power receiving control unit 292 of the
electronic device (or Wireless power receiver) 200 has two state
transitions so as to encode a data bit `1`, and has one state
transition so as to encode a data bit `0.` That is, the data bit
`1` may be encoded so that the transition between HI and LO states
occurs at rising and falling edges of the clock signal, and the
data bit `0` may be encoded so that the transition between HI and
LO states occurs at a rising edge of the clock signal.
[0255] Meanwhile, the power transmission control unit 112 may
obtain byte-unit data using a byte format in which a packet is
configured from a bit stream detected according to the bit encoding
method. In some embodiments, the detected bit stream may be a bit
stream transmitted using an 11-bit asynchronous serial format as
shown in FIG. 12B. That is, the bit stream contains a start bit
informing the start of a byte and a stop bit informing the stop of
the byte, and data bits b0 to b7 may be contained between the start
bit and the stop bit. A parity bit for checking an error of data
may be added to the bit stream. The byte-unit data constitute a
packet containing a power control message.
[0256] FIG. 13 illustrates a packet containing a power control
message used in a wireless power transfer method according to
embodiments of the present disclosure.
[0257] The packet 500 may include a preamble 510, a header 520, a
message 530 and a checksum 540.
[0258] The preamble 510 is used to perform synchronization with
dada received by the wireless power transfer apparatus (or Wireless
power transmitter) 100 and to exactly detect a start bit of the
header 520. The preamble 510 may be configured so that the same bit
is repeated. For example, the preamble 510 may be configured so
that the data bit `1` according to the DBP encoding is repeated 11
to 25 times.
[0259] The header 520 is used to indicate a type of the packet 500.
The size and kind of the message 530 may be determined based on a
value header 520 represented by the header 520. The header 520 is a
value having a certain value, and is positioned next to the
preamble 510. For example, the header 520 may have a one-byte
size.
[0260] The message 530 is configured to contain data determined
based on the header 520. The message 530 has a size determined
according to its kind.
[0261] The checksum 540 is used to detect an error that may occur
in the header 520 and the message 530 while a power control message
is transferred. The header 520 and the message 530, except the
preamble 510 for synchronization and the checksum 540 for error
checking, may be called as a command packet (command_packet).
[0262] Hereinafter, operational phases of the wireless power
transfer apparatus (or Wireless power transmitter) 100 and the
electronic device (or Wireless power receiver) 200 will be
described.
[0263] FIG. 14 illustrates operational phases of the wireless power
transfer apparatus (or Wireless power transmitter) 100 and the
electronic device (or Wireless power receiver) 200 according to
embodiments of the present disclosure. FIGS. 15 to 19 illustrate
structures of packets containing power control messages between the
wireless power transfer apparatus (or Wireless power transmitter)
100 and the electronic device (or Wireless power receiver) 200.
[0264] Referring to FIG. 14, the operational phases of the wireless
power transfer apparatus (or Wireless power transmitter) 100 and
the electronic device (or Wireless power receiver) 200 for the
purpose of wireless power transfer may be divided into a selection
phase 610, a ping phase 620, an identification and configuration
phase 630 and a power transfer phase 640.
[0265] In the selection phase 610, the wireless power transfer
apparatus (or Wireless power transmitter) 100 detects whether or
not objects exist within a range in which the wireless power
transfer apparatus (or Wireless power transmitter) 100 can transfer
power by wireless. In the ping phase 620, the wireless power
transfer apparatus (or Wireless power transmitter) 100 sends a
detection signal to the detected object, and the electronic device
(or Wireless power receiver) 200 sends a response for the detection
signal.
[0266] In the identification and configuration phase 630, the
wireless power transfer apparatus (or Wireless power transmitter)
100 identifies the electronic device (or Wireless power receiver)
200 selected through previous phases and obtains configuration
information for power transmission. In the power transfer phase
640, the wireless power transfer apparatus (or Wireless power
transmitter) 100 transfers power to the electronic device (or
Wireless power receiver) 200 while controlling power transferred
corresponding to the power control message received from the
electronic device (or Wireless power receiver) 200.
[0267] Hereinafter, each of the operational phases will be
described in detail.
[0268] 1) Selection Phase
[0269] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the selection phase 610 performs a detection
process for selecting the electronic device (or Wireless power
receiver) 200 existing in a semi-active area. The semi-active area,
as described above, refers to an area in which an object in the
corresponding area may have influence on the characteristic of
power of the power conversion unit 111. When comparing the
selection phase 610 with the ping phase 620, the detection process
for selecting the electronic device (or Wireless power receiver)
200 in the selection phase 610 is a process of detecting whether or
not an object exists within a certain range not by receiving a
response from the electronic device (or Wireless power receiver)
200 using a power control message but by detecting a change in
electrical energy for forming a wireless power signal in the power
conversion unit 111 of the power transfer apparatus 100. The
detection process in the selection phase 610 may be called as an
analog ping process in that an object is detected not using a
digital-format packet in the ping phase 620 which will be described
later but using a wireless power signal.
[0270] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the selection phase may detect that an object
enters into and exit from the semi-active area. The wireless power
transfer apparatus (or Wireless power transmitter) 100 may
distinguish the electronic device (or Wireless power receiver) 200
capable of transmitting power by wireless from other objects (e.g.,
a key, a coin, etc.) among the objects existing within the
semi-active area.
[0271] As described above, the distance at which the wireless power
transfer apparatus (or Wireless power transmitter) 100 can transfer
power by wireless according to the inductive coupling is different
from that at which the wireless power transfer apparatus (or
Wireless power transmitter) 100 can transfer power by wireless
according to the electromagnetic resonance coupling. Therefore, the
semi-active area in which the object is detected in the selection
phase 610 according to the inductive coupling may be different from
that in which the object is detected in the selection phase
according to the electromagnetic resonance coupling.
[0272] First, in embodiments in which power is transferred
according to the inductive coupling, the wireless power transfer
apparatus (or Wireless power transmitter) 100 in the selection
phase 610 may monitor an interface surface (not shown) so as to
detect the disposal and removal of objects.
[0273] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may detect the position of the electronic device
(or Wireless power receiver) 200 placed on the interface surface.
As described above, the wireless power transfer apparatus (or
Wireless power transmitter) 100 formed to include one or more
transfer coils may perform a method of proceeding to the ping phase
620 from the selection state 610 and identifying whether or not a
response for the detection signal is transferred from the object
using each of the coils, or may perform a method of proceeding to
the identification phase 630 from the ping phase 620 and
identifying whether or not identification information is
transferred from the object. The wireless power transfer apparatus
(or Wireless power transmitter) 100 may determine a coil to be used
in the wireless power transfer based on the position of the
detected electronic device (or Wireless power receiver) 200,
obtained by the process described above.
[0274] In embodiments in which power is transferred according to
the electromagnetic resonance coupling, the wireless power transfer
apparatus (or Wireless power transmitter) 100 in the selection
phase 610 may detect the object by sensing a change in one or more
of the frequency, current and voltage of the power conversion unit
111, caused by the object within the semi-active area.
[0275] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the selection phase 610 may detect the object
using at least one of the detection methods according the inductive
coupling and the electromagnetic resonance coupling. The wireless
power transfer apparatus (or Wireless power transmitter) 100 may
perform the object detection process according to each of the power
transfer methods and then select the method of detecting the object
from the detection methods according to the inductive coupling and
the electromagnetic resonance coupling so as to proceed to the
other phases 620, 630 and 640.
[0276] Meanwhile, the wireless power signal formed so that the
wireless power transfer apparatus (or Wireless power transmitter)
100 in the selection phase 610 detects the object may have its
frequency, intensity, etc., different from those of the wireless
power signal formed so that the wireless power transfer apparatus
(or Wireless power transmitter) 100 in the other phases 620, 630
and 640 performs digital detection, identification, configuration
and power transfer. Thus, the selection phase 610 of the wireless
power transfer apparatus (or Wireless power transmitter) 100
corresponds to an idle phase for detecting an object, so that the
wireless power transfer apparatus (or Wireless power transmitter)
100 can reduce power consumption in the air or generate a
specialized signal for the purpose of efficient object
detection.
[0277] 2) Ping Phase
[0278] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the ping phase 620 performs a process of an
electronic device (or Wireless power receiver) 200 existing within
the semi-active area through a power control message. When
comparing the detection process in the ping phase 620 with the
detection process in the selection phase 610, the detection process
in the ping phase 620 may be called as a digital ping process.
[0279] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the ping phase 620 forms a wireless power
signal for detecting the electronic device (or Wireless power
receiver) 200, demodulates the wireless power signal modulated by
the electronic device (or Wireless power receiver) 200, and obtains
a power control message in a digital data format, corresponding to
the response for the detection signal, from the demodulated
wireless power signal. The wireless power transfer apparatus (or
Wireless power transmitter) 100 can recognize the electronic device
(or Wireless power receiver) 200 that becomes an object of the
power transfer by receiving the power control message corresponding
to the response for the detection signal
[0280] The ping signal formed so that the wireless power transfer
apparatus (or Wireless power transmitter) 100 in the ping phase 620
perform the digital detection process may be a wireless power
signal formed by applying a power signal at a specific operating
point for a certain period of time. The operating point may mean
the frequency, duty cycle and amplitude of a voltage applied to the
transfer coil (Tx coil). The wireless power transfer apparatus (or
Wireless power transmitter) 100 may attempt to generates, for a
certain period of time, the detection signal generated by applying
the power signal at the specific operating point and to receive the
power control message from the electronic device (or Wireless power
receiver) 200.
[0281] Meanwhile, the power control message corresponding to the
response for the detection signal may be a message indicating the
strength of the wireless power signal received by the electronic
device (or Wireless power receiver) 200. For example, the
electronic device (or Wireless power receiver) 200 may transfer a
signal strength packet 5100 containing the message indicating the
strength of the wireless power signal received as the response for
the detection signal as shown in FIG. 15. The packet 5100 may be
configured to include a header 5120 for informing that the packet
5100 is a packet indicating the strength of a signal and a message
5130 indicating the strength of the power signal received by the
electronic device (or Wireless power receiver) 200. The strength of
the power signal in the message 5130 may be a value indicating a
degree of inductive coupling or electromagnetic resonance coupling
for power transfer between the wireless power transfer apparatus
(or Wireless power transmitter) 100 and the electronic device (or
Wireless power receiver) 200.
[0282] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may detect the electronic device (or Wireless
power receiver) 200 by receiving the response for the detection
signal and then proceed to the identification and configuration
phase 630 by extending the digital detection process. That is, the
wireless power transfer apparatus (or Wireless power transmitter)
100 may detect the electronic device (or Wireless power receiver)
200 and then receive a power control message required in the
identification and configuration phase 630 by maintaining the power
signal at the specific operating point.
[0283] However, when the wireless power transfer apparatus (or
Wireless power transmitter) 100 does not detect the electronic
device (or Wireless power receiver) 200 to which the wireless power
transfer apparatus (or Wireless power transmitter) 100 can transmit
power, the operating phase of the wireless power transfer apparatus
(or Wireless power transmitter) 100 may return to the selection
phase.
[0284] 3) Identification and Configuration Phase
[0285] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the identification and configuration phase 630
may control power transmission to be efficiently performed by
receiving identification information and/or configuration
information transferred by the electronic device (or Wireless power
receiver) 200.
[0286] In the identification and configuration phase 630, the
electronic device (or Wireless power receiver) 200 may transfer a
power control message containing its own identification
information. To this end, the electronic device (or Wireless power
receiver) 200 may transfer, for example, an identification packet
5200 containing a message indicating the identification information
of the electronic device (or Wireless power receiver) 200 as shown
in FIG. 16A. The packet 5200 may be configured to include a header
5200 for informing that the packet 5200 is a packet indicating the
identification information and a message 5230 containing the
identification information of the electronic device (or Wireless
power receiver) 200. The message 5230 may be configured to include
information 5231 and 5232 indicating the version of a contract for
wireless power transfer, information 5233 identifying a
manufacturer of the electronic device (or Wireless power receiver)
200, information indicating the presence of existence of an
extension device identifier and a basic device identifier 5235.
When the extension device identifier exists in the information 5234
indicating the present of existence of the extension device
identifier, an extended identification packet 5300 containing an
extension device identifier may be separately transferred as shown
in FIG. 16B. The packet 5300 may be configured to include a header
5320 for informing that the packet 5300 is a packet indicating the
extension device identifier and a message 5330 containing the
extension device identifier. When the extension device identifier
is used as described above, the identification information 5233 of
the manufacturer, the basic device identifier 5235 and the
information based on the extension device identifier 5330 may be
used to identify the electronic device (or Wireless power receiver)
200.
[0287] In the identification and configuration phase 630, the
electronic device (or Wireless power receiver) 200 may transfer a
power control message containing information on estimated maximum
power. To this end, the electronic device (or Wireless power
receiver) 200 may transfer, for example, a configuration packet
5400 as shown in FIG. 17. The packet 5400 may be configured to
include a header 5420 for informing that the packet 5400 is a
configuration packet and a message 5430 containing the information
on the estimated maximum power. The message 5430 may be configured
to include a power class 5431, information 5432 on estimated
maximum power, an indicator indicating a method of determining
current of a major cell of the wireless power transfer apparatus,
and the number (5434) of selective configuration packets. The
indicator 5433 may be an indicator indicating whether or not the
current of the main cell of the wireless power transfer apparatus
is to be determined as stated in the contract for wireless power
transfer.
[0288] Meanwhile, according to the embodiments of the present
disclosure, the electronic device (or Wireless power receiver) 200
may transfer, to the wireless power transfer apparatus (or Wireless
power transmitter) 100, a power control message containing
information on its own required power or information on its
profile. In some embodiments, the information on the required power
of the electronic device (or Wireless power receiver) 200 or
information on its profile may be transferred while being contained
in the configuration packet 5400 as shown in FIG. 17. In some
embodiments, the information on the required power of the
electronic device (or Wireless power receiver) 200 or information
on its profile may be transferred while being contained in a packet
for separate configuration.
[0289] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may generate a power transfer contract used in
power charging with the electronic device (or Wireless power
receiver) 200 based on the identification information and/or
configuration information. The power transfer contract may contain
limits of parameters for determining power transfer characteristics
in the power transfer phase 640.
[0290] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may finish the identification and configuration
phase 640 before proceeding to the power transfer phase 640, and
return to the selection phase 610. For example, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may finish
the identification and configuration phase 630 so as to detect
another electronic device capable of receiving power by
wireless.
[0291] 4) Power Transfer Phase
[0292] The wireless power transfer apparatus (or Wireless power
transmitter) 100 in the power transfer phase 640 transfers power to
the electronic device (or Wireless power receiver) 200.
[0293] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may receive a power control message from the
electronic device (or Wireless power receiver) 200 while
transferring the power to the electronic device, and control the
characteristic of power applied to the transfer coil, corresponding
to the received power control message. For example, the power
control message used to control the characteristic of the power
applied to the transfer coil may be contained in a control error
packet 5500 as shown in FIG. 18. The packet 5500 may be configured
to include a header 5520 for informing that the packet 5500 is a
control error packet and a message 5530 containing a control error
value. The wireless power transfer apparatus (or Wireless power
transmitter) 100 may control the power applied to the transfer coil
based on the control error value. That is, the current applied to
the transfer coil may be controlled to be maintained when the
control error value is 0, to be decreased when the control error
value is a negative value and to be increased when the control
error value is a positive value.
[0294] In the power transfer phase 640, the wireless power transfer
apparatus (or Wireless power transmitter) 100 may monitor
parameters in the power transfer contract generated based on the
identification information and/or configuration information. When
the power transfer between the wireless power transfer apparatus
(or Wireless power transmitter) 100 and the electronic device (or
Wireless power receiver) 200 violates the limits contained in the
power transfer contract as a result obtained by monitoring the
parameters, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may cancel the power transfer and return to
the selection phase 610.
[0295] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may finish the power transfer phase 640 based on
the power transfer message received from the electronic device (or
Wireless power receiver) 200.
[0296] In some embodiment, when the charging of a battery is
completed while the electronic device (or Wireless power receiver)
200 charges the battery using the transferred power, the electronic
device (or Wireless power receiver) 200 may transfer a power
control message for requesting the wireless power transfer
apparatus to stop the wireless power transfer. In this case, after
the wireless power transfer apparatus (or Wireless power
transmitter) 100 receives the message for requesting the wireless
power transfer apparatus (or Wireless power transmitter) 100 to
stop the wireless power transfer, the wireless power transfer
apparatus (or Wireless power transmitter) 100 may finish the
wireless power transfer and return to the selection phase 610.
[0297] In some embodiments, the electronic device (or Wireless
power receiver) 200 may transfer a power control message for
requesting the wireless power transfer apparatus (or Wireless power
transmitter) 100 of renegotiation or reconfiguration so as to renew
the previously generated power transfer contract. When the
electronic device (or Wireless power receiver) 200 requires power
having an amount larger or smaller than that of the currently
transferred power, the electronic device (or Wireless power
receiver) 200 may transfer a message for requesting the wireless
power transfer apparatus (or Wireless power transmitter) 100 of the
renegotiation of the power transfer contract. In this case, after
the wireless power transfer apparatus (or Wireless power
transmitter) 100 receives the message for requesting the wireless
power transfer apparatus (or Wireless power transmitter) 100 of the
renegotiation of the power transfer contract, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may finish
the wireless power transfer and return to the identification and
configuration phase 630.
[0298] To this end, the message transferred by the electronic
device (or Wireless power receiver) 200 may be, for example, an end
power transfer packet 5600 as shown in FIG. 19. The packet 5600 may
be configured to include a header 5620 for informing that the
packet 5600 is an end power transfer packet and a message 5630
containing an end power transfer code indicating a reason for the
end power transfer. The end power transfer code may indicate any
one of charge complete, internal fault, over temperature, over
voltage, over current, battery failure, reconfiguration, no
response and unknown failure.
[0299] Hereinafter, a method in which the wireless power transfer
apparatus periodically changes a frequency for wireless power
transfer will be described with reference to FIGS. 20 to 31.
[0300] Wireless Power Transfer Apparatus Having Function of
Periodically Changing Frequency
[0301] The wireless power transfer apparatus having a function of
periodically changing a frequency according to embodiments of the
present disclosure may include a power transmission unit forming a
wireless power signal for transferring wireless power based on a
carrier signal, and a control unit determining a sweep frequency
range and sweep period for the carrier signal and controlling the
power transmission unit so that the frequency of the wireless power
signal is periodically changed by periodically changing the
frequency of the carrier signal based on the determined sweep
frequency range and sweep period.
[0302] Various regulations may exist in a wireless power transfer
technology using a magnetic field.
[0303] Particularly, the wireless power transfer technology may be
regulated by electromagnetic compatibility (EMC), and numerical
values regulated for each country and region may also have
different values.
[0304] A method using frequencies corresponding to industrial,
scientific and medical (ISM) bands may exist as a method used to
avoid or overcome the EMC regulation. For example, a method using
6.78 MHz, 13.56 MHz, etc. may be used in the wireless power
transfer.
[0305] A method using a frequency band of a few hundreds of KHz as
another frequency band may be used in the wireless power transfer
technology. When such a frequency band is used, the wireless power
transfer technology may be regulated by CISPR 11 (Industrial,
scientific and medical equipment--Radio-frequency disturbance
characteristics--Limits and methods of measurement) rather than
FCC, etc. In this case, the magnetic field intensity in a low
frequency band may be strongly regulated by the CISPR 11.
[0306] Thus, the wireless power transfer apparatus according to the
embodiments of the present disclosure can decrease the magnetic
field intensity in a specific frequency band by periodically
changing the frequency of a wireless power signal. This is may be
called as frequency sweep. In other words, this may be called as
dithering for the frequency of the wireless power signal. A spread
spectrum technology may be applied to the frequency sweep of the
wireless power signal.
[0307] Specifically, the wireless power transfer apparatus may
periodically change the frequency of the wireless power signal by
periodically changing the frequency of a carrier signal that
becomes the basis for forming the wireless power signal.
[0308] Hereinafter, a method of sweeping the frequency of the
wireless power signal will be described in detail.
[0309] FIG. 20 is a block diagram illustrating a configuration of
the wireless power transfer apparatus for configuring a frequency
according to embodiments of the present disclosure.
[0310] FIG. 20 illustrates the wireless power transfer apparatus
further comprising additional components in addition to the
components shown in FIG. 2A.
[0311] As can be seen with reference to FIG. 20, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may include
the power transmission unit (or wireless transmission unit) 110
supporting one or more of the inductive coupling the
electromagnetic resonance coupling and the control unit (or
Controller) 180.
[0312] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may further include the power supply unit 190, the
sensor unit 120, the communication unit 130, the output unit 140
and the memory 140 so as to perform a configuration function of the
transfer frequency of a wireless power signal.
[0313] In addition, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may further include various
components for performing a frequency configuration function.
[0314] Hereinafter, the components will be sequentially
described.
[0315] The power transmission unit 110 may function to form a
wireless power signal for transferring wireless power based on a
carrier signal.
[0316] Specifically, a process of generating the wireless power
signal will be described. The power transmission unit 110 may
include the power conversion unit 111, and the power conversion
unit 111 may include the transfer coil (Tx coil) 1111b, the
inverter 1112 and the resonance generation circuit 1116. The
inverter 1112 may be connected to the transfer coil 1111b and the
resonance generation circuit 1116.
[0317] The inverter 1112 transforms a DC input obtained from the
power supply unit 190 to an AC waveform. The AC current transformed
by the inverter 112 drives a resonance circuit including the
transfer coil (Transmitting coil or Tx coil) 1111a and a capacitor
(not shown), so that a magnetic field is formed in the transfer
coil (Transmitting coil or Tx coil) 1111a. The wireless power
signal can be transmitted from the wireless power transfer
apparatus (or Wireless power transmitter) 100 to the wireless power
receiving apparatus 200 due to the formed magnetic field.
[0318] According to an embodiment, the AC waveform generated in the
inverter 1112 may be a carrier signal. The carrier signal drives
the resonance circuit, and the wireless power signal may be
generated from the transfer coil (Transmitting coil or Tx coil)
1111a by driving the resonance circuit. That is, the wireless power
signal may be formed based on the carrier signal.
[0319] The power transmission unit 110 may change the frequency of
the wireless power signal by periodically changing the frequency of
the carrier signal based on a sweep frequency range and sweep
period determined by the control unit (or Controller) 180.
[0320] The wireless power transfer apparatus (or Wireless power
transmitter) 100 according to the embodiments of the present
disclosure may be applied not only to a unidirectional
communication wireless power transfer system but also to a
bidirectional communication wireless power transfer system.
[0321] When the wireless power transfer apparatus (or Wireless
power transmitter) 100 is applied to bidirectional communication,
the power transmission unit 110 may transfer a wireless power
signal and obtain power transfer information from the wireless
power receiving apparatus 200 receiving the wireless power
signal.
[0322] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may generate a transfer profile based on the power
transfer information obtained by the wireless power receiving
device 200, and determine the sweep frequency range and sweep
period based on the transfer profile. For example, the sweep
frequency range may be a frequency range in which the
receiving-side voltage is the first reference voltage or less and
the second reference voltage or more.
[0323] The power transmission unit 110 may obtain power transfer
information using various methods. For example, the power
transmission unit 110 may sequentially transfer wireless power
signals having different frequencies and obtain power transfer
information corresponding to each of the sequentially transferred
wireless power signals. Such a method may be called as frequency
scanning.
[0324] Thus, the relationship between the frequency of the wireless
power signal and the power transfer information can be detected
through the frequency scanning, and the transfer frequency of the
wireless power signal can be configured based on the detected
relationship.
[0325] According to an embodiment, the power transfer information,
the power transfer information may include information related to
at least one of the receiving-side voltage of the wireless power
receiving apparatus 200, the receiving current of the wireless
power receiving apparatus 200, the first reference voltage and the
second reference voltage.
[0326] The receiving-side voltage and the receiving-side current
may mean voltage and current existing in the wireless power
receiving apparatus 200. For example, the receiving-side voltage
and the receiving-side current may be output voltage and current of
the receiving coil (or Rx coil) 2911a.
[0327] According to an embodiment of the present disclosure, the
first reference voltage and the second reference voltage may be
voltage information related to the receiving-side (or
receiving-terminal) voltage of the wireless power receiving
apparatus 200.
[0328] According to an embodiment, the first reference voltage is
determined based on whether or not the first reference voltage is a
voltage that may cause damage on the wireless power receiving
apparatus 200, and the second reference voltage is determined based
on whether or not the second reference voltage is a voltage at
which the wireless power receiving apparatus 200 can receive
wireless power from the wireless power transfer apparatus (or
Wireless power transmitter) 100.
[0329] For example, when there exists a possibility that the damage
of the wireless power receiving apparatus 200 may be caused at a
receiving-side voltage of 100V or more, the first reference voltage
may be 100V. That is, the first reference voltage may be a
receiving-side minimum voltage that may cause damage.
[0330] For example, when the wireless power receiving apparatus 200
cannot normally receive wireless power at a receiving-side voltage
of 10V or less, the second reference voltage may be 10V. That is,
the second reference voltage may be a receiving-side minimum
voltage at which the wireless power receiving apparatus 200 can
normally operate.
[0331] The control unit (or Controller) 180 may perform various
functions for performing a sweep (or dithering) function for the
transfer frequency of the wireless power signal.
[0332] For example, the control unit (or Controller) 180 may
control the power transmission unit 110, the sensor unit 120, the
communication unit 130, the output unit 140, the memory 150 and the
power supply unit 190 so as to perform the sweep function for the
transfer frequency of the wireless power signal.
[0333] The control unit (or Controller) 180 may be implemented in
various forms. For example, the control unit (or Controller) 180
may be implemented as a module separate from the power transmission
control unit 112 in the power transmission unit 110 described with
reference to FIG. 2 or may be implemented as a single module.
[0334] According to embodiments of the present disclosure, the
control unit (or Controller) 180 determine the sweep frequency
range and sweep period of the carrier signal.
[0335] The control unit (or Controller) 180 may control the power
transmission unit 110 so as to change the frequency of the wireless
power signal by periodically changing the frequency of the carrier
signal based to the determined sweep frequency range and sweep
period.
[0336] In this case, the frequency of the wireless power signal may
be periodically changed (or swept) by periodically changing the
frequency of the carrier signal.
[0337] As described above, there may occur an effect that the
frequency spectrum of the wireless power signal is spread by the
frequency sweep of the wireless power signal. Accordingly, the
magnetic field intensity is decreased in a specific frequency band,
so that it is possible to more easily cope with the EMC
regulation.
[0338] The control unit (or Controller) 180 may generate a transfer
profile based on the power transfer information obtained by the
wireless power receiving apparatus 200.
[0339] The control unit (or Controller) 180 may determine the sweep
frequency range or sweep period based on the transfer profile.
[0340] Here, the transfer profile may represent a relationship
between the frequency of the wireless power signal and at least one
of the receiving-side voltage, a transfer efficiency and a transfer
gain.
[0341] Here, the transfer efficiency may be a ratio between the
transfer power of the wireless power transfer apparatus and the
receiving power of the wireless power receiving apparatus, and the
transfer gain may be a ratio between the transmitting-side voltage
of the wireless power transfer apparatus and the receiving-side
voltage of the wireless power receiving apparatus.
[0342] Specifically, the control unit (or Controller) 180 may
determine the sweep frequency range or sweep period based on the
characteristic of the transfer profile. For example, when the
transfer gain at a specific frequency is maximized due to the
characteristic of the transfer profile, the control unit (or
Controller) 180 may determine a certain frequency range including
the specific frequency as the sweep frequency range. For example,
when the fast spread effect of a spectrum is required because the
maximum transfer gain is extremely large due to the characteristic
of the transfer profile, the sweep period may be reduced (or the
sweep period may be determined so as to obtain the fast spread
effect of the spectrum.
[0343] The control unit (or Controller) 180 may configure a
specific frequency in the sweep frequency range to the transfer
frequency of the wireless power signal. The specific frequency may
be a frequency selected in the frequency sweeping process. For
example, when the sweep frequency range is 10 to 11 MHz, a unit
sweep frequency (or swept unit frequency) is 0.1 MHz and the
existing frequency (or transfer frequency) of the wireless power
signal is 10 MHz, the specific frequency may be determined as 10.1
MHz.
[0344] The control unit (or Controller) 180 may control the power
transmission unit 110 to transfer a wireless power signal
corresponding to the specific frequency to the wireless power
receiving apparatus.
[0345] The control unit (or Controller) 180 may determine a sweep
period for the carrier signal. The control unit (or Controller) 180
may determine the sweep period using various references or methods.
For example, the sweep period may be a sweep period determined
based on a user selection input. In this case, the sweep period may
be determined in consideration of EMC, and may be determined based
on the transfer gain or transfer efficiency for a frequency.
[0346] The sweep period may be determined based on the transfer
profile. For example, when the spread effect of the spectrum
necessarily occurs for a fast period of time due to the
characteristic of the transfer profile, the sweep period may be
configured to be shorter.
[0347] The method of determining the sweep frequency range or sweep
period based on the transfer profile will be described in detail
with reference to FIGS. 25 to 27.
[0348] The sensor unit 120 may include a sensor for sensing the
position of the wireless power receiving apparatus 200. Information
on the position of the wireless power receiving apparatus 200,
sensed by the sensor unit 120, may be used so that the power
transmission unit 110 can efficiently transmit power.
[0349] For example, in the wireless power transmission according to
the embodiments supporting the inductive coupling, the sensor unit
120 may operate as a position detection unit. The information on
the position sensed by the sensor unit 120 may be used to move or
rotate the transfer coil (Transmitting coil or Tx coil) 1111a in
the power conversion unit 111.
[0350] For example, the wireless power transfer apparatus (or
Wireless power transmitter) 100 according to the embodiments
configured to the one or more transfer coils described above may
determine coils, among the one or more transfer coils, which may be
in the inductive coupling relationship or electromagnetic resonance
coupling relationship with the receiving coil of the electronic
device.
[0351] Meanwhile, the sensor unit 120 may be configured to monitor
whether or not the electronic device (or Wireless power receiver)
200 comes close to an area in which charging is possible. The
function of sensing whether or not the sensor unit 120 comes close
may be performed separately from or combined with the function that
the power transmission control unit 112 in the power transmission
unit 110 senses whether or not the electronic device comes
close.
[0352] The communication unit 130 performs wire/wireless data
communication with the electronic device (or Wireless power
receiver) 200. The communication unit 130 may include electronic
components for one or more of Bluetooth.TM., Zigbee, UWB, wireless
USB, NFC and wireless LAN.
[0353] The output unit 140 includes at least one of a display unit
141 and a sound output unit (or Audio output unit) 142. The display
unit 141 may include at least one of an LCD, a TFT LCD, an OLED, a
flexible display and a 3D display. The display unit 141 may display
a charging state under a control of the control unit (or
Controller) 180.
[0354] The memory 150 may include a storage medium of at least one
of a flash memory type, a hard disk type, a multimedia card micro
type, a card type memory (e.g., an SD or XD memory, etc.), a RAM,
an SRAM, a ROM, an EEPROM, a programmable read-only memory (PROM),
a magnetic memory, a magnetic disk and an optic disk. The wireless
power transfer apparatus (or Wireless power transmitter) 100.
Programs or commands executing the aforementioned functions of the
wireless power transfer apparatus (or Wireless power transmitter)
100 may be stored in the memory 150. The control unit (or
Controller) 180 may execute the programs or commands stored in the
memory 150 so as to transfer power by wireless. A memory controller
(not shown) may be used so that other components (e.g., the control
unit (or Controller) 180) included in the wireless power transfer
apparatus (or Wireless power transmitter) 100 access the memory
150.
[0355] Meanwhile, the wireless power transfer apparatus (or
Wireless power transmitter) 100 for changing a frequency according
to the embodiments of the present disclosure may be implemented in
the form of the wireless power transfer apparatus shown in FIG.
2A.
[0356] Specifically, the power conversion unit 111 may perform the
frequency scanning (meaning the aforementioned method) in a certain
frequency range, obtain power transfer information on the frequency
subjected to the frequency scanning in the certain frequency from
the wireless power receiving apparatus 200, and transfer power by
wireless according to the configured operating frequency (or
transfer frequency).
[0357] The power transmission control unit 112 may determine
whether or not to obtain power transfer information. That is,
according to an embodiment, the power transfer information may be
obtained when at least one of the receiving-side voltage, the
transfer efficiency and the transfer gain is a reference value or
less, when the number of wireless power receiving apparatuses
existing in the specific area is changed, when the position of at
least one wireless power receiving apparatus is changed or when a
request received from the wireless power receiving apparatus
periodically or temporarily exists.
[0358] For example, the power transmission control unit may
determine whether or not to obtain the power transfer information
by determining whether or not the transfer efficiency of the
transferred power is a predetermined value or less or whether or
not a certain time elapses when the power transfer information is
periodically obtained.
[0359] Here, the specific area may mean an area through which the
wireless power signal passes or an area in which the wireless power
receiving apparatus 200 may be detected (or the aforementioned
active area or semi-active area).
[0360] The transfer efficiency may be a ratio between the transfer
power of the wireless power transfer apparatus and the receiving
power of the wireless power receiving apparatus, and the transfer
gain may be a ratio between the transmitting-side voltage of the
wireless power transfer apparatus and the receiving-side voltage of
the wireless power receiving apparatus. The receiving power may be
detected based on receiving-side voltage information and
receiving-side current information.
[0361] The power transmission control unit 112 may configure a
transfer frequency (or operational frequency) for transferring
power by wireless through the power conversion unit 111 based on
the power transfer information. Specifically, the power
transmission control unit 112 may determine a sweep frequency range
based on the transfer profile generated based on the power transfer
information, and a specific frequency in the sweep frequency may be
configured as the transfer frequency. As described above, the
specific frequency may be a frequency selected so that a frequency
sweeping function (or spread effect of a frequency spectrum)
occurs.
[0362] The power transmission control unit 112 may detect the
presence of existence of the wireless power receiving apparatus 200
in the specific area using the wireless power signal generated by
the power conversion unit 111. Alternatively, the power
transmission control unit 112 may detect the presence of the
wireless power receiving apparatus 200 using a separate detection
unit (not shown).
[0363] Method of Changing Frequency of Wireless Power Signal
According to Embodiments of the Present Disclosure
[0364] The method of changing the frequency of a wireless power
signal according to embodiments of the present disclosure may
include generating wireless power signal for transferring wireless
power based on a carrier signal, determining a sweep frequency
range and sweep period for the carrier signal, and periodically
changing the frequency of the wireless power signal by periodically
changing the frequency of the carrier signal based on the
determined sweep frequency range and sweep period.
[0365] The sweep frequency range may be determined in various
manners.
[0366] According to an embodiment, the determining of the sweep
frequency range may include obtaining power transfer information
from a wireless power receiving apparatus receiving the wireless
power signal, generating a transfer profile based on the obtained
power transfer information, and determining the sweep frequency
range based on the generated transfer profile.
[0367] According to an embodiment, the determining of the sweep
frequency range may include extracting, as a reference frequency, a
frequency of which primary differential value is `0` and secondary
differential value is a negative number with respect to at least
one the receiving-side voltage, the transfer efficiency and the
transfer gain, and determining the sweep frequency range based on
the reference frequency.
[0368] FIG. 21 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to embodiments of
the present disclosure.
[0369] Referring to FIG. 21, the method of changing the frequency
of a wireless power signal according to the embodiments of the
present disclosure may include the following steps.
[0370] First, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a wireless power signal for
transferring wireless power based on a carrier signal (S110).
[0371] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep frequency range and
sweep period for the carrier signal (S120).
[0372] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may periodically change the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the determined sweep frequency range and
sweep period (S130).
[0373] FIG. 22 is an exemplary view illustrating a method of
changing the frequency of a wireless power signal according to an
embodiment of the present disclosure.
[0374] Referring to FIG. 22(a), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may transfer a
wireless power signal W110 through the transfer coil (Transmitting
coil or Tx coil) 1111a, and the wireless power receiving apparatus
may receive the wireless power signal W110 through the receiving
coil (or Rx coil) 2911a.
[0375] Specifically, the power transmission unit 110 included in
the wireless power transfer apparatus (or Wireless power
transmitter) 100 generates a carrier signal and drives the transfer
coil (Transmitting coil or Tx coil) 1111a (or drives a resonance
circuit including the transfer coil (Transmitting coil or Tx coil)
1111a). The transfer coil (Transmitting coil or Tx coil) 1111a may
transfer, to the receiving coil (or Rx coil) 2911a, a wireless
power signal generated based on the carrier signal.
[0376] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may determine a sweep frequency range and
frequency period for the carrier signal so as to sweep the
frequency of the wireless power signal.
[0377] The wireless power transfer apparatus (or Wireless power
transmitter) 100 (or the control unit (or Controller) 180) may
control the power transmission unit 110 so that the frequency of
the wireless power signal is periodically changed by periodically
changing the frequency of the carrier signal based on the
determined sweep frequency range and sweep period.
[0378] The sweep frequency range and the sweep frequency may be
determined in various manners.
[0379] For example, the sweep frequency range may be a frequency
range including a predetermined frequency. Here, the predetermined
frequency may be a frequency representing a resonance frequency or
maximum wireless power transfer efficiency in the wireless power
transfer.
[0380] Referring to FIG. 22(b), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may determine, as the
sweep frequency range, a frequency range wb1 to wb2 including a
frequency wa (or peak frequency) having a maximum transfer
efficiency .eta.max in the graph showing a relationship between the
frequency of the wireless power signal and transfer efficiency
.eta..
[0381] The graph showing the relationship between the frequency of
the wireless power signal and transfer efficiency .eta. may be a
transfer profile. According to an embodiment, the transfer profile
may represent a relationship between the frequency of the wireless
power signal and at least on of the receiving-side voltage and the
transfer gain as well as the transfer efficiency. The transfer
efficiency may be a ratio between the transfer power of the
wireless power transfer apparatus and the receiving power of the
wireless power receiving apparatus, and the transfer gain may be a
ratio between the transmitting-side voltage of the wireless power
transfer apparatus and the receiving-side voltage of the wireless
power receiving apparatus.
[0382] The transfer profile may be generated based on the power
transfer information obtained from the wireless power receiving
apparatus 200. The transfer profile may be a transfer profile
obtained based on an experimental value (e.g., an experiment for
obtaining a relationship of transfer efficiency for each
frequency).
[0383] Here, the power transfer information may include information
related to at least one of a receiving-side voltage of the wireless
power receiving apparatus, a receiving-side current of the wireless
power receiving apparatus, a first reference voltage and a second
reference voltage. The first reference voltage may be determined
based on whether or not the first reference voltage is a voltage
that may cause damage on the wireless power receiving apparatus,
and the second reference voltage may be determined based on whether
or not the second reference voltage is a voltage at which the
wireless power receiving apparatus can receive wireless power from
the wireless power transfer apparatus.
[0384] Referring to FIG. 22(c), the sweep frequency range is a
frequency range between first and second maximum frequencies. The
first maximum frequency may be a frequency representing maximum
wireless power transfer efficiency within a first frequency range,
and the second maximum frequency may be a frequency representing
maximum wireless power transfer efficiency within a second
frequency range.
[0385] Specifically, when the transfer profile representing the
transfer efficiency .eta. includes two peak points (or maximum
values .eta.m1 and .eta.m2 within a specific period), the sweep
frequency range may be determined based on two frequencies
respectively corresponding to the two peak points .eta.m1 and
.eta.m2. For example, the frequency range .DELTA.wm (wm1-wm2)
between the two frequencies may be determined as the sweep
frequency range.
[0386] As shown in FIG. 22(c), the principle (or frequency split
phenomenon) representing two peak points (or two maximum points) on
the transfer profile may be as follows.
[0387] FIGS. 23 and 24 are views illustrating a frequency split
phenomenon occurring between a transfer coil of the wireless power
transfer apparatus and a receiving coil of the wireless power
receiving apparatus.
[0388] Referring to FIG. 23, a wireless power signal is generated
between the transfer coil 1111 and the receiving coil 2911 in the
wireless power transfer apparatus (or Wireless power transmitter)
100. The physical characteristic of the wireless power signal
generated between the transfer coil 1111 and the receiving coil
2911 may be represented differently depending on a wireless power
transfer method between the coils.
[0389] For example, a wireless power signal according to inductive
coupling is generated between the transfer coil 1111 and the
receiving coil 2911 so as to transfer power, the wireless power
signal may be a magnetic signal obtained according to the area A1
formed by the transfer coil 1111, the radius r1 of the transfer
coil, the number of turns N1 of the transfer coil 1111, the area
formed by the receiving coil 2911, the radius r2 of the receiving
coil 2911, the number of turns N2 of the receiving coil 2911 and
the distance z between the transfer coil 1111 and the receiving
coil 2911.
[0390] Generally, when power is transferred by a magnetic field
formed between the transfer coil 1111 and the receiving coil 2911,
a characteristic in which a power transfer gain is high in the
vicinity of the resonance frequency of the magnetic field is shown
between both the coils.
[0391] However, a frequency split characteristic having a plurality
of peaks in the vicinity of the resonance frequency according to
the distance between the transfer coil 1111 and the receiving coil
2911, magnetic characteristic of the wireless power receiving
apparatus or the number of wireless power receiving apparatuses may
be shown between both the coils.
[0392] Specifically, the frequency split characteristic in which
peaks are formed at the first and second frequencies w1 and w2 in
the vicinity of the resonance frequency w may be shown in a
transfer gain curve in the wireless power transfer between the
transfer coil 1111 and the receiving coil 2911. The frequency split
characteristic may be expressed by the following Equation 2
representing the first and second frequencies w1 and w2.
.omega..sub.1,2=.omega..+-. {square root over
(.kappa..sup.2-.GAMMA..sup.2)} Equation 2
[0393] Here, .kappa. denotes a coupling coefficient between the two
coils, and .GAMMA. denotes a degree of dissipation caused by a
medium between the two coils. From Equation 2, the coupling
coefficient may be expressed by the following Equation 3.
.omega. 2 - .omega. 1 = .DELTA..omega. = 2 .kappa. 2 - .GAMMA. 2
.kappa. = ( .DELTA..omega. 2 ) 2 + .GAMMA. 2 Equation 3
##EQU00002##
[0394] The equations may be approximated by the following Equation
4.
.omega. 2 - .omega. .apprxeq. .kappa. , .kappa. = 2 .kappa. .omega.
= M L 1 L 2 .apprxeq. .DELTA..omega. .omega. = .omega. 2 - .omega.
1 .omega. Equation 4 ##EQU00003##
[0395] Referring to FIG. 24, when the frequency split
characteristic described above is shown, the peaks are not formed
in the vicinity of the resonance frequency w but formed at the
first and second frequencies w1 and w2, and therefore, the
frequency of which transfer efficiency is maximized may be
changed.
[0396] The peak frequency (or maximum transfer efficiency frequency
wa, wm1 or wm2) on the transfer profile of FIGS. 22(b) and 22(c)
may be extracted (or detected) in various manners. For example, the
peak frequency wa, wm1 or wm2 may be extracted using a method of
evaluating the maximum value of a function.
[0397] Specifically, the wireless power transfer apparatus (or
Wireless power transmitter) 100 (or the control unit (or
Controller) 180) may extract, as a reference frequency, a frequency
of which primary differential value is 0' and secondary
differential value is a negative number with respect to at least
one the receiving-side voltage, the transfer efficiency and the
transfer gain, and determine the sweep frequency range based on the
reference frequency. Here, the control unit (or Controller) 180 may
determine a specific frequency range including the reference
frequency as the sweep frequency range. The reference frequency
includes a first frequency (or first maximum frequency) and a
second frequency (or second maximum frequency), and the sweep
frequency range may be a frequency range between the first and
second frequencies.
[0398] For example, in FIG. 22(b), to evaluate a maximum value on
the transfer profile, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may calculate primary and secondary
differential values for the frequency with respect to the transfer
efficiency on the transfer profile, and determine, as the reference
frequency, the frequency wa of which primary differential value is
`0` and secondary differential value is a negative value. In this
case, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may determine a certain (or specific) frequency
range .DELTA.wa (wb1-wb2) including the reference frequency as the
sweep frequency range.
[0399] For example, in FIG. 22(c), to evaluate a maximum value on
the transfer profile, may calculate primary and secondary
differential values for the frequency with respect to the transfer
efficiency on the transfer profile, and determine, as the reference
frequencies (e.g., the first and second maximum frequencies wm1 and
wm2), the frequencies wm1 and wm2 of which primary differential
values become `0` and secondary differential values become a
negative value. In this case, the wireless power transfer apparatus
(or Wireless power transmitter) 100 may determine a frequency range
.DELTA.wm (wm1-wm2) between the reference frequencies as the sweep
frequency range.
First Embodiment
Determination of Sweep Frequency Range Based on Transfer
Profile
[0400] The first embodiment of the present disclosure may be
implemented with a portion or combination of the components or
steps included in the aforementioned embodiments or may be
implemented with a combination of the aforementioned embodiments.
Hereinafter, overlapping portions may be omitted for clarity of the
first embodiment of the present disclosure.
[0401] The wireless power transfer apparatus having a function of
periodically changing a frequency according to the first embodiment
of the present disclosure may include a power transmission unit
forming a wireless power signal for transferring wireless power
based on a carrier signal, and a control unit determining a sweep
frequency range and sweep period for the carrier signal and
controlling the power transmission unit so that the frequency of
the wireless power signal is periodically changed by periodically
changing the frequency of the carrier signal based on the
determined sweep frequency range and sweep period.
[0402] According to the first embodiment, the power transmission
unit may obtain power transfer information from a wireless power
receiving apparatus receiving the wireless power signal, and the
control unit may generate a transfer profile based on the obtained
power transfer information and determine the sweep frequency range
based on the transfer profile.
[0403] FIG. 25 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to the first
embodiment of the present disclosure.
[0404] Referring to FIG. 25, the method of changing a frequency of
the wireless power transfer apparatus according to the first
embodiment of the present disclosure may include the following
steps.
[0405] First, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a wireless power signal for
transferring wireless power based on a carrier signal (S110).
[0406] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may obtain power transfer information from a
wireless power receiving apparatus receiving the wireless power
signal (S121).
[0407] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a transfer profile based on the
obtained power transfer information (S122).
[0408] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep period corresponding
to the carrier signal (S123).
[0409] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep frequency range based
on the transfer profile (S124).
[0410] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may periodically change the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the determined sweep frequency range and
sweep period (S130).
[0411] Here, the power transfer information may include information
related to at least one of a receiving-side voltage of the wireless
power receiving apparatus, a receiving-side current of the wireless
power receiving apparatus, a first reference voltage and a second
reference voltage. The first reference voltage may be determined
based on whether or not the first reference voltage is a voltage
that may cause damage on the wireless power receiving apparatus,
and the second reference voltage may be determined based on whether
or not the second reference voltage is a voltage at which the
wireless power receiving apparatus can receive wireless power from
the wireless power transfer apparatus.
[0412] The power transmission unit 110 may sequentially transfer
wireless power signals having different frequencies and obtain
power transfer information corresponding to each of the
sequentially transferred wireless power signals. Such a method may
be called as frequency scanning.
[0413] Through the frequency scanning, the relationship between the
frequency of the wireless power signal and the power transfer
information can be detected, and the transfer profile can be
generated based on the detected relationship.
[0414] FIG. 26 is an exemplary view illustrating transfer profiles
according to the first embodiment of the present disclosure.
[0415] Referring to FIG. 26, the transfer profile may represent a
relationship between the frequency of the wireless power signal and
at least one of the receiving-side voltage, a transfer efficiency
and a transfer gain.
[0416] In FIG. 26(a), the transfer profile represents a
relationship between the frequency co of the wireless power signal
and the receiving-side voltage Vin of the wireless power receiving
apparatus 200.
[0417] In this case, it can be seen that the receiving-side voltage
Vin is changed depending on a change in the frequency .omega. of
the wireless power signal.
[0418] Here, Vmax is a maximum receiving-side voltage on the
transfer profile, and Vmin is a minimum receiving-side voltage on
the transfer profile. The Vmin may mean a minimum voltage at which
the wireless power receiving apparatus 200 can receive wireless
power from the wireless power transfer apparatus. According to an
embodiment, the second reference voltage may become the Vmin.
[0419] The minimum frequencies .omega.L and .omega.H may mean
frequencies at which the receiving-side voltage become the
Vmin.
[0420] In FIG. 26(b), the transfer profile represents a
relationship between the frequency .omega. of the wireless power
signal and transfer efficiency .eta..
[0421] In this case, it can be seen that the transfer efficiency
.eta. is changed depending on a change in the frequency .omega. of
the wireless power signal.
[0422] Here, .eta.max may be a maximum transfer efficiency on the
transfer profile, and .eta.min may be a minimum transfer efficiency
on the transfer profile.
[0423] According to an embodiment, when the receiving-side voltage
becomes the second reference voltage, the transfer efficiency .eta.
may become the .eta.min.
[0424] The minimum frequencies .omega.L and .omega.H may mean
frequencies at which the transfer efficiency .eta. becomes the
.eta.min.
[0425] According to the first embodiment, the transfer efficiency
may be a ratio between the transfer power of the wireless power
transfer apparatus (or Wireless power transmitter) 100 and the
receiving power of the wireless power receiving apparatus 200.
[0426] According to the first embodiment, the receiving power may
be detected based on the receiving-side voltage information and
receiving-side current information. For example, the wireless power
transfer apparatus (or Wireless power transmitter) 100 may
calculate the receiving power by multiplying values of the
receiving-side voltage and receiving-side current in the obtained
power transfer information.
[0427] In FIG. 26(c), the transfer profile represents a
relationship between the frequency co of the wireless power signal
and transfer gain A.
[0428] Here, Amax may be a maximum transfer gain, and Amin may be a
minimum transfer gain.
[0429] According to an embodiment, when the receiving-side voltage
becomes the second reference voltage, the transfer gain A may
become the Amin.
[0430] The minimum frequencies .omega.L and .omega.H may mean
frequencies at which the transfer gain A becomes the Amin.
[0431] According to the first embodiment, the transfer gain A may
be a ratio between the transmitting-side voltage and receiving-side
voltage of the wireless power transfer apparatus.
[0432] The wireless power transfer apparatus (or Wireless power
transmitter) 100 according to the first embodiment may determine
the sweep frequency range based on the transfer profile described
above.
[0433] FIG. 27 is an exemplary view illustrating a method of
determining a sweep frequency range according to the first
embodiment of the present disclosure.
[0434] FIG. 27(a) illustrates a case in which the transfer profile
represents a relationship between the frequency of the wireless
power signal and the receiving-side voltage Vin of the wireless
power receiving apparatus.
[0435] Referring to FIG. 27(a), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may determine, as the
sweep frequency range, a frequency range corresponding to a range
in which the receiving-side voltage Vin is the first reference
voltage V1 and the second reference voltage V2 or more.
[0436] To this end, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may obtain receiving-side voltage
information that is one of the power transfer information from the
wireless power receiving apparatus 200, and generated a transfer
profile shown in FIG. 27(a) based on the receiving-side voltage
information. The wireless power transfer apparatus (or Wireless
power transmitter) 100 may extract a frequency range in which the
receiving side voltage Vin is the first reference voltage V1 or
less and the second reference voltage V2 or more on the generated
transfer profile, and determine the extracted frequency range as
the sweep frequency range.
[0437] Here, the first reference voltage may be determined based on
whether or not the first reference voltage is a voltage that may
cause damage on the wireless power receiving apparatus, and the
second reference voltage may be determined based on whether or not
the second reference voltage is a voltage at which the wireless
power receiving apparatus can receive wireless power from the
wireless power transfer apparatus.
[0438] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may detect a maximum point on the generated
transfer profile and determine a frequency corresponding to the
maximum point as a reference frequency. The wireless power transfer
apparatus (or Wireless power transmitter) 100 may determine the
sweep frequency range based on the reference frequency. For
example, the reference frequency includes first and second
frequencies, and the sweep frequency range may be a frequency range
between the first and second frequencies.
[0439] In this case, the reference frequency may be a frequency
representing the maximum transfer efficiency (or maximum transfer
gain to maximum receiving-side voltage) on the transfer profile (or
may be a frequency at which the maximum transfer efficiency is
represented within a certain frequency range).
[0440] The number of maximum points (or reference frequencies) on
the transfer profile may be at least one. For example, the
frequencies corresponding to the respective maximum points may be
first and second maximum frequencies. The first maximum frequency
may be a frequency representing the maximum wireless power transfer
efficiency within a first frequency range, and the second maximum
frequency may be a frequency representing the maximum wireless
power transfer in a second frequency range.
[0441] The reference frequency (or frequency corresponding to the
maximum point) may be extracted in various manners. For example,
the reference frequency may be determined by selecting the maximum
point on the transfer profile through a user's selection input. For
example, the reference frequency may be determined by mathematical
calculation.
[0442] According to the first embodiment, the wireless power
transfer apparatus (or Wireless power transmitter) 100 (or the
control unit (or Controller) 180) may extract, as a reference
frequency, a frequency of which primary differential value is 0'
and secondary differential value is a negative number with respect
to at least one the receiving-side voltage, the transfer efficiency
and the transfer gain, and determine the sweep frequency range
based on the reference frequency.
[0443] FIG. 27(b) illustrates a case in which the transfer profile
represents a relationship between the frequency of the wireless
power signal and transfer efficiency .eta. and the number of
reference frequencies is 1 (or the number of frequencies
corresponding to the maximum transfer efficiency is 1).
[0444] Referring to FIG. 27(b), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may obtain a transfer
efficiency .eta. that is one of the power transfer information from
the wireless power receiving apparatus 200, and generate a transfer
profile shown in FIG. 27(b) based on the obtained transfer
efficiency .eta..
[0445] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may extract primary and secondary differential
values with respect to the generated transfer profile, and
determine, as a reference frequency wam, a frequency of which
primary differential value `0` and secondary differential value is
a negative value.
[0446] The wireless power transfer apparatus (or Wireless power
transmitter) 100 (or the control unit (or Controller) 180) may
determine a specific frequency range .DELTA.wam=wa1-wa2 including
the reference frequency wam as the sweep frequency range.
[0447] According to the first embodiment, the specific frequency
range may be determined based on whether or not the wireless power
receiving apparatus can receive wireless power from the wireless
power transfer apparatus based on at least on of the receiving-side
voltage, the transfer efficiency and the transfer gain. For
example, as shown in FIG. 27(b), the specific frequency range may
be determined based on the frequencies wa1 and wa2 representing the
minimum transfer efficiency .eta.min.
[0448] FIG. 27(c) illustrates a case in which the transfer profile
represents a relationship between the frequency of the wireless
power signal and the receiving-side voltage Vin and the number of
reference frequencies is 2 (or the number of frequencies
corresponding to the maximum transfer efficiency is 2).
[0449] Referring to FIG. 27(c), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may generate a
transfer profile shown in FIG. 27(c) based on the receiving-side
voltage information obtained from the wireless power receiving
apparatus 200.
[0450] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may determine frequencies respectively
corresponding to two maximum points on the generated transfer
profile as first and second reference frequencies wp1 and wp2.
[0451] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may determine, as the sweep frequency range, a
frequency range .DELTA.wp12 between the first and second reference
frequencies wp1 and wp2.
[0452] According to the first embodiment, the reference frequencies
may include N frequencies, and the wireless power transfer
apparatus (or Wireless power transmitter) 100 (or the control unit
(or Controller) 180) may select two frequencies from the N
frequencies and determine the frequency range between the selected
two frequencies as the sweep frequency range.
[0453] FIG. 27(d) illustrates a case in which the transfer profile
represents a relationship between the frequency of the wireless
power signal and transfer gain A and the N is 3.
[0454] Referring to FIG. 27(d), the wireless power transfer
apparatus (or Wireless power transmitter) 100 two frequencies waa
and wac from three reference frequencies (or frequencies
respectively corresponding to maximum points) waa, wab and wac.
[0455] According to the first embodiment, the selected two
frequencies may be two frequencies closest to the resonance
frequency we among the N frequencies in the wireless power
transfer.
[0456] In this case, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may determine, as the sweep
frequency range, a frequency range .DELTA.wc12 between the two
selected frequencies waa and wac.
[0457] According to the first embodiment, the reference frequency
may include N frequencies, and the wireless power transfer
apparatus (or Wireless power transmitter) 100 (or the control unit
(or Controller) 180) may select a specific frequency from the N
frequencies and determine a specific frequency range including the
specific frequency as the sweep frequency range.
[0458] Here, the specific frequency may be a frequency at which at
least one of the receiving-side voltage, the transfer efficiency
and the transfer gain is maximized or a frequency closest to the
resonance frequency among the N frequencies in the wireless power
transfer.
[0459] The specific frequency range may be determined based on
whether or not the wireless power receiving apparatus can receive
wireless power from the wireless power transfer apparatus based on
at least one of the receiving-side voltage, the transfer efficiency
and the transfer gain.
[0460] FIG. 27(e) illustrates a case in which the transfer profile
represents a relationship between the frequency of the wireless
power signal and transfer gain A and the N is 3.
[0461] Referring to FIG. 27(e), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may obtain transfer
gain information from the wireless power receiving apparatus 200
and generate a transfer profile shown in FIG. 27(e) based on the
obtained transfer gain information.
[0462] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may extract three reference frequencies ws1, wsm
and ws2 on the generated transfer profile.
[0463] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may select a specific frequency wsm from the three
reference frequencies, and may determine, the sweep frequency
range, a specific frequency range .DELTA.ws including the specific
frequency wsm.
[0464] Here, the specific frequency may be a frequency at which the
transfer gain is maximized (case of FIG. 27(e)) or a frequency
closest to the resonance frequency among the three frequencies in
the wireless power transfer.
Second Embodiment
Determination of Sweep Frequency Range when Plurality of Receiving
Apparatuses Exist
[0465] The second embodiment of the present disclosure may be
implemented with a portion or combination of the components or
steps included in the aforementioned embodiments or may be
implemented with a combination of the aforementioned embodiments.
Hereinafter, overlapping portions may be omitted for clarity of the
second embodiment of the present disclosure.
[0466] The wireless power transfer apparatus having a function of
periodically changing a frequency according to the second
embodiment of the present disclosure may include a power
transmission unit forming a wireless power signal for transferring
wireless power based on a carrier signal, and a control unit
determining a sweep frequency range and sweep period for the
carrier signal and controlling the power transmission unit so that
the frequency of the wireless power signal is periodically changed
by periodically changing the frequency of the carrier signal based
on the determined sweep frequency range and sweep period.
[0467] According to the second embodiment, the wireless power
receiving apparatus may include a plurality of wireless power
receiving apparatuses, and the control unit may generate a
plurality of transfer profiles respectively corresponding to the
plurality of wireless power receiving apparatuses based on the
power transfer information.
[0468] FIG. 28 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to the second
embodiment of the present disclosure.
[0469] Referring to FIG. 28, the method of changing the frequency
of a wireless power signal according to the second embodiment of
the present disclosure may include the following steps.
[0470] First, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a wireless power signal for
transferring wireless power based on a carrier signal (S110).
[0471] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may obtain power transfer information from a
plurality of wireless power receiving apparatuses receiving the
wireless power signal (S210).
[0472] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a plurality of transfer
profiles respectively corresponding to the plurality of wireless
power receiving apparatuses based on the power transfer information
(S220).
[0473] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep period corresponding
to the carrier signal (S230).
[0474] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep frequency range based
on the plurality of transfer profiles (S240).
[0475] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may periodically change the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the sweep frequency range and sweep period
(S130).
[0476] According to the second embodiment, the determining of the
sweep frequency range based on the plurality of transfer profiles
may be performed in various manners (or methods).
[0477] For example, the wireless power transfer apparatus (or
Wireless power transmitter) 100 (or the control unit (or
Controller) 180) may select at least one transfer profile from the
plurality of transfer profiles, and determine the sweep frequency
range based on the selected at least one transfer profile. Here,
the selecting of the at least one transfer profile from the
plurality of transfer profiles may be performed based on at least
one of whether or not damage on the wireless power receiving
apparatus may be caused and whether or not the wireless power
receiving apparatus may receive the wireless power from the
wireless power transfer apparatus.
[0478] For example, the wireless power transfer apparatus (or
Wireless power transmitter) 100 (or the control unit (or
Controller) 180) may generate a reference transfer profile based on
the plurality of transfer profiles, and determine the sweep
frequency range based on the generated reference transfer profile.
Here, the reference transfer profile may be generated by processing
the plurality of transfer profiles using a statistical method.
[0479] FIG. 29 is an exemplary view illustrating the method of
changing the frequency of the wireless power signal according to
the second embodiment of the present disclosure.
[0480] Referring to FIG. 29(a), the wireless power transfer
apparatus (or Wireless power transmitter) 100 may select one
transfer profile L130 from a plurality of transfer profiles L110 to
L140.
[0481] The selecting of the one transfer profile L130 from a
plurality of transfer profiles L110 to L140 may be performed based
on at least one of whether or not damage on the wireless power
receiving apparatus 200 may be caused and whether or not the
wireless power receiving apparatus 200 may receive the wireless
power from the wireless power transfer apparatus (or Wireless power
transmitter) 100.
[0482] For example, in FIG. 29, the first and second transfer
profiles L110 and L120 show a distribution in which the
receiving-side voltage of the wireless power transfer receiving
apparatus is entirely high. Therefore, in consideration of whether
or not damage on the wireless power receiving apparatus 200 may be
caused, the wireless power transfer apparatus (or Wireless power
transmitter) 100 may not select the first and second transfer
profiles L110 and L120.
[0483] For example, the fourth transfer profile L140 shows a
distribution in which the receiving-side voltage of the wireless
power receiving apparatus 200 is entirely low. Therefore, in
consideration of whether or not the wireless power receiving
apparatus 200 may receive the wireless power from the wireless
power transfer apparatus (or Wireless power transmitter) 100, the
wireless power transfer apparatus (or Wireless power transmitter)
100 may not select the fourth transfer profile L140.
[0484] Thus, the wireless power transfer apparatus (or Wireless
power transmitter) 100 can select the third transfer profile L130
in consideration of whether or not damage on the wireless power
receiving apparatus 200 may be caused and whether or not the
wireless power receiving apparatus 200 may receive the wireless
power from the wireless power transfer apparatus (or Wireless power
transmitter) 100.
[0485] The wireless power transfer apparatus (or Wireless power
transmitter) 100 may determine the sweep frequency range based on
the selected third transfer profile L130 using the method disclosed
in the aforementioned embodiments.
[0486] Referring to FIG. 29(b), the wireless power transfer
apparatus (or Wireless power transmitter) 100 (or the control unit
(or Controller) 180) may generate a reference transfer profile L220
based on a plurality of transfer profiles L210 and L230.
[0487] Specifically, the wireless power transfer apparatus (or
Wireless power transmitter) 100 may generate the reference transfer
profile L220 by processing the plurality of transfer profiles L210
and L230 using a statistical method.
[0488] The processing of the plurality of transfer profiles L210
and L230 using the statistical method may be performed in various
manners. For example, the statistical method may be a method based
on the average, dispersion and standard deviation of the plurality
of transfer profiles L210 and L230. In addition, it will be
apparent to those skilled in the art that various statistical
methods may be applied to the method of changing the frequency of
the wireless power signal according to the embodiment of the
present disclosure.
[0489] FIG. 29(b) illustrates a case in which the wireless power
transfer apparatus (or Wireless power transmitter) 100 determines
an average transfer profile of the plurality of transfer profiles
L210 and L230 as the reference transfer profile L220.
Third Embodiment
Data Transfer Using Sweep Period
[0490] The third embodiment of the present disclosure may be
implemented with a portion or combination of the components or
steps included in the aforementioned embodiments or may be
implemented with a combination of the aforementioned embodiments.
Hereinafter, overlapping portions may be omitted for clarity of the
second embodiment of the present disclosure.
[0491] The wireless power transfer apparatus having a function of
periodically changing a frequency according to the third embodiment
of the present disclosure may include a power transmission unit
forming a wireless power signal for transferring wireless power
based on a carrier signal, and a control unit determining a sweep
frequency range and sweep period for the carrier signal and
controlling the power transmission unit so that the frequency of
the wireless power signal is periodically changed by periodically
changing the frequency of the carrier signal based on the
determined sweep frequency range and sweep period.
[0492] According to the third embodiment, the sweep period may
include a plurality of sub-sweep periods, and the control unit may
select a specific sub-sweep period from the plurality of sub-sweep
periods based on data to be transferred to a wireless power
receiving apparatus and control the power transmission unit to
change the frequency of the wireless power signal by periodically
changing the frequency of the carrier signal based on the selected
specific sub-sweep period.
[0493] FIG. 30 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to the third
embodiment of the present disclosure.
[0494] Referring to FIG. 30, the method of changing the frequency
of a wireless power signal according to the third embodiment of the
present disclosure may include the following steps.
[0495] First, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may generate a wireless power signal for
transferring wireless power based on a carrier signal (S110).
[0496] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may determine a sweep frequency range for
the carrier signal (S310).
[0497] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may select a specific sweep period from a
plurality of sub-sweep periods based on data to be transferred to
the wireless power receiving apparatus 200 (S320).
[0498] Next, the wireless power transfer apparatus (or Wireless
power transmitter) 100 may periodically change the frequency of the
wireless power signal by periodically changing the frequency of the
carrier signal based on the sweep frequency range and the specific
sweep period (S330).
[0499] FIG. 31 is an exemplary view illustrating the method of
changing the frequency of the wireless power signal according to
the third embodiment of the present disclosure.
[0500] Referring to FIG. 31, the power transmission unit 110
included in the wireless power transfer apparatus (or Wireless
power transmitter) 100 may drive a resonance circuit based on a
carrier signal C110 and generate a wireless power signal w210
through the transfer coil (Transmitting coil or Tx coil) 1111a
included in the resonance circuit.
[0501] The wireless power signal w210 may be transferred to the
receiving coil (or Rx coil) 2911a of the wireless power receiving
apparatus 200.
[0502] The control unit (or Controller) 180 included in the
wireless power transfer apparatus (or Wireless power transmitter)
100 may determine a sweep frequency range and sweep period for the
carrier signal.
[0503] In this case, the wireless power transfer apparatus (or
Wireless power transmitter) 100 according to the third embodiment
may transfer data to the wireless power receiving apparatus 200 by
changing the sweep period. That is, the wireless power transfer
apparatus (or Wireless power transmitter) 100 may modulate the
wireless power signal by changing the sweep period, and transfer
data to the wireless power receiving apparatus 200 through the
modulation.
[0504] Specifically, the sweep period for the carrier signal may
include a plurality of sub-sweep periods T1 and T2.
[0505] The control unit (or Controller) 180 may select a specific
sub-sweep period (e.g., T1) from the plurality of sub-sweep periods
T1 and T2 based on the data to be transferred to the wireless power
receiving apparatus 200, and control the power transmission unit
110 to periodically change the frequency of the wireless power
signal by periodically changing the frequency of the carrier signal
based on the selected specific sub-sweep period T1.
[0506] Here, the plurality of sub-sweep periods are the first and
second sub-sweep periods T1 and T2. The first sub-sweep period T1
may be a period corresponding to data `0,` and the second sub-sweep
period T2 may be a period corresponding to data `1.`
[0507] In this case, the wireless power receiving apparatus 200 may
detect the specific sub-sweep period T1 from the wireless power
signal w210 and recover the transferred data based on the detected
specific sub-sweep period.
[0508] For example, in FIG. 31, a case in which the wireless power
transfer apparatus (or Wireless power transmitter) 100 intends to
sequentially transfer the data `0` and `1` to the wireless power
receiving apparatus 200 will be described. To transfer the data
`0,` the wireless power transfer apparatus (or Wireless power
transmitter) 100 may select the first sub-sweep period T1 as the
sweep period, and periodically change the frequency of the wireless
power signal w210 by periodically changing the frequency of the
carrier signal based on the first sub-sweep period T1. In this
case, the period in which the frequency of the wireless power
signal is changed may be T1.
[0509] To transfer the data `1,` the wireless power transfer
apparatus (or Wireless power transmitter) 100 may select the second
sub-sweep period T2 as the sweep period, and periodically change
the frequency of the wireless power signal w210 by periodically
changing the frequency of the carrier signal based on the second
sub-sweep period T2. Here, the period in which the frequency of the
wireless power signal is changed may be T2.
[0510] The wireless power receiving apparatus 200 may detect the
sweep period of the wireless power signal w210. For example, the
wireless power receiving apparatus 200 may sequentially detect the
sweep period of the wireless power signal w210 as T1 and T2.
[0511] In this case, the wireless power receiving apparatus 200 may
recover data corresponding to T1 as `0,` and recover data
corresponding to T2 as `1.`
[0512] As such, the wireless power transfer apparatus (or Wireless
power transmitter) 100 according to the third embodiment can
transfer specific data to the wireless power receiving apparatus
200 by changing the sweep period for the carrier signal.
[0513] The methods described above may be implemented in a
recording medium readable by a computer or device similar to the
computer, for example, using software, hardware or combination of
the software and hardware.
[0514] According to the implementation using the hardware, the
methods described above may be implemented using at least one of
application specific integrated circuits (ASICs), digital signal
processors (DSPs), digital signal processing devices (DSPDs),
programmable logic devices (PLDs), field programmable gate arrays
(FPGAs), processors, controllers, electrical units for performing
other functions. For example, the methods may be implemented by the
control unit (or Controller) 180 or power transmission control unit
112 of the wireless power transfer apparatus (or Wireless power
transmitter) 100.
[0515] According to the implementation using the software, the
embodiments such as procedures and functions described in the
present disclosure may be implemented with separate software
modules. Each of the software modules may perform one or more
functions and operations described in the present disclosure.
Software codes may be implemented using a software application
written by an appropriate programming language. The software codes
may be stored in the memory of the wireless power transfer
apparatus (or Wireless power transmitter) 100, and may be performed
by the control unit (or Controller) 180 or the power transmission
control unit 112.
[0516] It will be readily understood by those skilled in the art
that the configuration of the wireless power transfer apparatus
according to the embodiments of the present disclosure may be
applied to devices such as a docking station, a terminal cradle
device and other electronic devices, except that the configuration
of the wireless power transfer apparatus is applicable to only the
wireless charger.
[0517] The scope of the present invention is not limited to the
embodiments disclosed in this specification, and it will be
understood by those skilled in the art that various changes and
modifications can be made thereto within the technical spirit and
scope defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0518] FIG. 1 is an exemplary view conceptually illustrating a
wireless power transfer apparatus and an electronic device
according to embodiments of the present disclosure;
[0519] FIGS. 2A and 2B are block diagrams illustrating
configurations of the wireless power transfer apparatus and the
electronic device, applicable in embodiments of the present
disclosure, respectively;
[0520] FIG. 3 illustrates a concept that power is transmitted by
wireless from the wireless power transfer apparatus to the
electronic device according to inductive coupling;
[0521] FIGS. 4A and 4B are a block diagram illustrating portions of
the configurations of the wireless power transfer apparatus and the
electronic device using electromagnetic induction, applicable in
embodiments of the present disclosure;
[0522] FIG. 5 is a block diagram of the wireless power transfer
apparatus configured to have one or more transfer coils for
receiving power according to the inductive coupling, applicable in
embodiments of the present disclosure;
[0523] FIG. 6 illustrates a concept that power is transmitted by
wireless from the wireless power transfer apparatus to the
electronic device according to electromagnetic resonance
coupling;
[0524] FIGS. 7A and 7B are a block diagram illustrating portions of
the configurations of the wireless power transfer apparatus and the
electronic device using the electromagnetic resonance coupling,
applicable in embodiments of the present disclosure;
[0525] FIG. 8 is a block diagram of the wireless power transfer
apparatus configured to have one or more transfer coils for
receiving power according to the electromagnetic resonance
coupling, applicable in embodiments of the present disclosure;
[0526] FIG. 9 is a block diagram of the wireless power transfer
apparatus further including additional components except the
components shown in FIG. 2A;
[0527] FIG. 10 is illustrates a configuration of the electronic
device implemented in the form of a mobile terminal according to
embodiments of the present disclosure;
[0528] FIGS. 11A and 11B illustrate a concept that packets are
transmitted/received between the wireless power transfer apparatus
and the electronic device through modulation and demodulation of a
wireless power signal in wireless power transmission;
[0529] FIGS. 12A and 12B illustrate a method in which the wireless
power transfer apparatus displays data bits and bytes constituting
a power control message;
[0530] FIG. 13 illustrates a packet containing a power control
message used in a wireless power transfer method according to
embodiments of the present disclosure;
[0531] FIG. 14 illustrates operational phases of the wireless power
transfer apparatus and the electronic device according to
embodiments of the present disclosure;
[0532] FIGS. 15 to 19 illustrate structures of packets containing
power control messages between the wireless power transfer
apparatus and the electronic device;
[0533] FIG. 20 is a block diagram illustrating a configuration of
the wireless power transfer apparatus for configuring a frequency
according to embodiments of the present disclosure;
[0534] FIG. 21 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to embodiments of
the present disclosure;
[0535] FIG. 22 is an exemplary view illustrating a method of
changing the frequency of a wireless power signal according to an
embodiment of the present disclosure;
[0536] FIGS. 23 and 24 are views illustrating a frequency split
phenomenon occurring between a transfer coil of the wireless power
transfer apparatus and a receiving coil of the wireless power
receiving apparatus;
[0537] FIG. 25 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to a first
embodiment of the present disclosure;
[0538] FIG. 26 is an exemplary view illustrating transfer profiles
according to the first embodiment of the present disclosure;
[0539] FIG. 27 is an exemplary view illustrating a method of
determining a sweep frequency range according to the first
embodiment of the present disclosure;
[0540] FIG. 28 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to a second
embodiment of the present disclosure;
[0541] FIG. 29 is an exemplary view illustrating the method of
changing the frequency of the wireless power signal according to
the second embodiment of the present disclosure;
[0542] FIG. 30 is a flowchart illustrating a method of changing the
frequency of a wireless power signal according to a third
embodiment of the present disclosure; and
[0543] FIG. 31 is an exemplary view illustrating the method of
changing the frequency of the wireless power signal according to
the third embodiment of the present disclosure.
* * * * *